feat: Phase 2 – Benutzerverwaltung (CRUD-API, Profil, UI)

README.md

@@ -2,7 +2,7 @@
 
 Zentrale, webbasierte Management-Plattform, über die eigenständige Web-Applikationen als **Module** integriert, verwaltet und Benutzern zugewiesen werden können.
 
-**Status: Phase 1 – Grundgerüst (abgeschlossen)**
+**Status: Phase 2 – Benutzerverwaltung (abgeschlossen)**
 
 ## Architektur-Überblick
 
@@ -87,7 +87,15 @@ MPM/
 | Backend | NestJS 11, TypeScript, REST `/api/v1`, OpenAPI/Swagger |
 | Datenbank | PostgreSQL 18 (Schemas: `management`, ab Phase 3 pro Modul) |
 | Betrieb | Docker, Nginx, Supervisor, unprivilegierter Benutzer |
-| Sicherheit | Argon2id, HttpOnly/Secure/SameSite-Cookies, serverseitige Sessions, CSRF-Schutz, Rate Limiting, Account Lockout, Audit-Log, Helmet |
+| Sicherheit | Argon2id, HttpOnly/Secure/SameSite-Cookies, serverseitige Sessions, CSRF-Schutz, Rate Limiting, Account Lockout, Audit-Log, Helmet, RBAC |
+
+## Funktionen
+
+### Phase 1 – Grundgerüst
+Login/Logout mit serverseitigen Sessions, Rollen (ADMIN/USER), Health-Monitoring, Audit-Log, Migrationen mit Advisory-Lock, responsive Management-UI mit Design-System.
+
+### Phase 2 – Benutzerverwaltung
+Vollständige Benutzer-CRUD-API (nur Admin) mit Duplikat-Schutz, Schutz des letzten Admins, sofortiger Session-Sperrung bei Deaktivierung, Passwort-Reset, eigenes Passwort ändern, Benutzerverwaltungs-UI (Tabelle, Modals, Toasts) und Profil-Seite.
 
 ## Annahme
 

apps/platform-backend/src/audit/audit.service.ts

@@ -7,6 +7,13 @@ export const AUDIT_ACTIONS = {
   LOGIN_FAILED: 'LOGIN_FAILED',
   LOGIN_LOCKED: 'LOGIN_FAILED_LOCKED',
   LOGOUT: 'LOGOUT',
+  USER_CREATED: 'USER_CREATED',
+  USER_UPDATED: 'USER_UPDATED',
+  USER_ENABLED: 'USER_ENABLED',
+  USER_DISABLED: 'USER_DISABLED',
+  USER_DELETED: 'USER_DELETED',
+  USER_PASSWORD_RESET: 'USER_PASSWORD_RESET',
+  USER_PASSWORD_CHANGED: 'USER_PASSWORD_CHANGED',
 } as const;
 
 export type AuditAction = (typeof AUDIT_ACTIONS)[keyof typeof AUDIT_ACTIONS];

apps/platform-backend/src/auth/session.service.ts

@@ -73,6 +73,18 @@ export class SessionService {
     await this.database.query('DELETE FROM sessions WHERE id = $1', [sessionId]);
   }
 
+  /** Löscht alle Sessions eines Benutzers (Deaktivierung, Passwort-Reset). */
+  async deleteAllForUser(userId: string, exceptSessionId?: string): Promise<void> {
+    if (exceptSessionId) {
+      await this.database.query('DELETE FROM sessions WHERE user_id = $1 AND id <> $2', [
+        userId,
+        exceptSessionId,
+      ]);
+      return;
+    }
+    await this.database.query('DELETE FROM sessions WHERE user_id = $1', [userId]);
+  }
+
   /** Löscht alle abgelaufenen Sessions (Aufräumjob, später via Cron). */
   async deleteExpired(): Promise<void> {
     await this.database.query('DELETE FROM sessions WHERE expires_at <= now()');

apps/platform-backend/src/common/zod-validation.pipe.ts

@@ -17,11 +17,21 @@ export class ZodValidationPipe implements PipeTransform {
   transform(value: unknown, _metadata: ArgumentMetadata): unknown {
     const result = this.schema.safeParse(value);
     if (!result.success) {
+      const flattened = result.error.flatten();
+      const details: Record<string, string[]> = {};
+      for (const [key, messages] of Object.entries(flattened.fieldErrors)) {
+        if (messages) {
+          details[key] = messages;
+        }
+      }
+      if (flattened.formErrors.length > 0) {
+        details.form = flattened.formErrors;
+      }
       throw new BadRequestException({
         statusCode: 400,
         message: 'Validierung fehlgeschlagen',
         error: 'Bad Request',
-        details: result.error.flatten().fieldErrors,
+        details,
       });
     }
     return result.data;

apps/platform-backend/src/users/profile.controller.ts

@@ -0,0 +1,62 @@
+import { Body, Controller, Get, Patch, Req } from '@nestjs/common';
+import type { Request } from 'express';
+import { ApiTags } from '@nestjs/swagger';
+import type { AuthenticatedRequest } from '../auth/authenticated-request';
+import { CurrentUser } from '../common/decorators/current-user.decorator';
+import { ZodValidationPipe } from '../common/zod-validation.pipe';
+import type { AuthUser, RoleName, UserRecord } from './user.types';
+import { changePasswordSchema, type ChangePasswordDto } from './user.types';
+import { ProfileService } from './profile.service';
+
+/** Profil-Daten in API-Antworten. */
+interface ProfileResponse {
+  id: string;
+  username: string;
+  email: string;
+  displayName: string;
+  role: RoleName;
+  lastLoginAt: string | null;
+  createdAt: string;
+}
+
+function toProfileResponse(user: UserRecord): ProfileResponse {
+  return {
+    id: user.id,
+    username: user.username,
+    email: user.email,
+    displayName: user.displayName,
+    role: user.role,
+    lastLoginAt: user.lastLoginAt ? user.lastLoginAt.toISOString() : null,
+    createdAt: user.createdAt.toISOString(),
+  };
+}
+
+/**
+ * Profil des angemeldeten Benutzers (jede Rolle).
+ * Passwort-Änderung erfordert das aktuelle Passwort.
+ */
+@ApiTags('Profile')
+@Controller({ path: 'api/v1/profile' })
+export class ProfileController {
+  constructor(private readonly profileService: ProfileService) {}
+
+  @Get()
+  async getProfile(@CurrentUser() user: AuthUser): Promise<{ profile: ProfileResponse }> {
+    const profile = await this.profileService.getProfile(user.id);
+    return { profile: toProfileResponse(profile) };
+  }
+
+  @Patch('password')
+  async changePassword(
+    @CurrentUser() user: AuthUser,
+    @Req() request: AuthenticatedRequest & Request,
+    @Body(new ZodValidationPipe(changePasswordSchema)) body: ChangePasswordDto,
+  ): Promise<{ success: true }> {
+    const sessionId = request.session?.id;
+    if (!sessionId) {
+      throw new Error('Session-Kontext fehlt');
+    }
+    await this.profileService.changePassword(user.id, sessionId, body, request.ip ?? null);
+    return { success: true };
+  }
+}

apps/platform-backend/src/users/profile.service.spec.ts

@@ -0,0 +1,121 @@
+import { UnauthorizedException } from '@nestjs/common';
+import { AUDIT_ACTIONS, AuditService } from '../audit/audit.service';
+import { SessionService } from '../auth/session.service';
+import { PasswordHasher } from './password-hasher';
+import { UserRepository } from './user.repository';
+import type { UserRecord } from './user.types';
+import { ProfileService } from './profile.service';
+
+/** Erzeugt einen Benutzer-Datensatz für Tests. */
+function createUserRecord(overrides: Partial<UserRecord> = {}): UserRecord {
+  return {
+    id: 'user-1',
+    username: 'max',
+    email: 'max@example.com',
+    passwordHash: 'not-a-real-hash',
+    displayName: 'Max Mustermann',
+    role: 'USER',
+    isActive: true,
+    failedLoginAttempts: 0,
+    lockedUntil: null,
+    lastLoginAt: null,
+    createdAt: new Date(),
+    updatedAt: new Date(),
+    ...overrides,
+  };
+}
+
+/** Mock des UserRepository. */
+class MockUserRepository {
+  public user: UserRecord | null = createUserRecord();
+  public updatedPasswords: Array<{ id: string; hash: string }> = [];
+
+  async findById(id: string): Promise<UserRecord | null> {
+    return this.user && this.user.id === id ? this.user : null;
+  }
+
+  async updatePassword(id: string, hash: string): Promise<void> {
+    this.updatedPasswords.push({ id, hash });
+  }
+}
+
+/** Mock des SessionService. */
+class MockSessionService {
+  public deletedForUser: Array<{ userId: string; exceptSessionId?: string }> = [];
+
+  async deleteAllForUser(userId: string, exceptSessionId?: string): Promise<void> {
+    this.deletedForUser.push({ userId, exceptSessionId });
+  }
+}
+
+/** Mock des AuditService. */
+class MockAuditService {
+  public records: Array<{ action: string }> = [];
+
+  async record(entry: { action: string }): Promise<void> {
+    this.records.push(entry);
+  }
+}
+
+describe('ProfileService', () => {
+  let userRepository: MockUserRepository;
+  let sessionService: MockSessionService;
+  let auditService: MockAuditService;
+  let profileService: ProfileService;
+  let passwordHasher: PasswordHasher;
+
+  beforeEach(async () => {
+    userRepository = new MockUserRepository();
+    sessionService = new MockSessionService();
+    auditService = new MockAuditService();
+    passwordHasher = new PasswordHasher();
+    profileService = new ProfileService(
+      userRepository as unknown as UserRepository,
+      passwordHasher,
+      sessionService as unknown as SessionService,
+      auditService as unknown as AuditService,
+    );
+
+    userRepository.user = createUserRecord({
+      passwordHash: await passwordHasher.hash('Altes-Passwort-1'),
+    });
+  });
+
+  it('gibt das Profil des angemeldeten Benutzers zurück', async () => {
+    const profile = await profileService.getProfile('user-1');
+    expect(profile.username).toBe('max');
+  });
+
+  it('wirft UnauthorizedException bei unbekanntem Benutzer', async () => {
+    await expect(profileService.getProfile('unbekannt')).rejects.toThrow(
+      UnauthorizedException,
+    );
+  });
+
+  it('ändert das Passwort mit korrektem aktuellen Passwort', async () => {
+    await profileService.changePassword(
+      'user-1',
+      'session-1',
+      { currentPassword: 'Altes-Passwort-1', newPassword: 'Neues-Passwort-123' },
+      '127.0.0.1',
+    );
+
+    expect(userRepository.updatedPasswords).toHaveLength(1);
+    expect(sessionService.deletedForUser).toEqual([
+      { userId: 'user-1', exceptSessionId: 'session-1' },
+    ]);
+    expect(auditService.records.at(-1)?.action).toBe(AUDIT_ACTIONS.USER_PASSWORD_CHANGED);
+  });
+
+  it('lehnt falsches aktuelles Passwort ab', async () => {
+    await expect(
+      profileService.changePassword(
+        'user-1',
+        'session-1',
+        { currentPassword: 'falsch', newPassword: 'Neues-Passwort-123' },
+        null,
+      ),
+    ).rejects.toThrow(UnauthorizedException);
+    expect(userRepository.updatedPasswords).toHaveLength(0);
+  });
+});

apps/platform-backend/src/users/profile.service.ts

@@ -0,0 +1,61 @@
+import { Injectable, UnauthorizedException } from '@nestjs/common';
+import { AUDIT_ACTIONS, AuditService } from '../audit/audit.service';
+import { SessionService } from '../auth/session.service';
+import { PasswordHasher } from './password-hasher';
+import { UserRepository } from './user.repository';
+import type { ChangePasswordDto, UserRecord } from './user.types';
+
+/**
+ * Profil-Verwaltung des angemeldeten Benutzers:
+ * Eigenes Passwort ändern (mit Verifikation des aktuellen Passworts).
+ * Nach der Änderung werden alle übrigen Sessions des Benutzers
+ * ungültig gemacht – die aktuelle Session bleibt aktiv.
+ */
+@Injectable()
+export class ProfileService {
+  constructor(
+    private readonly userRepository: UserRepository,
+    private readonly passwordHasher: PasswordHasher,
+    private readonly sessionService: SessionService,
+    private readonly auditService: AuditService,
+  ) {}
+
+  async getProfile(userId: string): Promise<UserRecord> {
+    const user = await this.userRepository.findById(userId);
+    if (!user) {
+      throw new UnauthorizedException('Nicht authentifiziert');
+    }
+    return user;
+  }
+
+  async changePassword(
+    userId: string,
+    currentSessionId: string,
+    input: ChangePasswordDto,
+    ipAddress: string | null,
+  ): Promise<void> {
+    const user = await this.userRepository.findById(userId);
+    if (!user) {
+      throw new UnauthorizedException('Nicht authentifiziert');
+    }
+
+    const currentPasswordValid = await this.passwordHasher.verify(
+      user.passwordHash,
+      input.currentPassword,
+    );
+    if (!currentPasswordValid) {
+      throw new UnauthorizedException('Aktuelles Passwort ist falsch');
+    }
+
+    const newPasswordHash = await this.passwordHasher.hash(input.newPassword);
+    await this.userRepository.updatePassword(userId, newPasswordHash);
+    await this.sessionService.deleteAllForUser(userId, currentSessionId);
+
+    await this.auditService.record({
+      userId,
+      username: user.username,
+      action: AUDIT_ACTIONS.USER_PASSWORD_CHANGED,
+      ipAddress,
+    });
+  }
+}

apps/platform-backend/src/users/user.repository.ts

@@ -1,7 +1,7 @@
 import { Injectable } from '@nestjs/common';
 import { DatabaseService } from '../database/database.service';
 import { PasswordHasher } from './password-hasher';
-import type { AuthUser, RoleName, UserRecord } from './user.types';
+import type { CreateUserDto, RoleName, UpdateUserDto, UserRecord } from './user.types';
 
 interface UserRow {
   id: string;
@@ -22,20 +22,11 @@ const USER_COLUMNS = `u.id, u.username, u.email, u.password_hash, u.display_name
                       u.is_active, u.failed_login_attempts, u.locked_until,
                       u.last_login_at, u.created_at, u.updated_at`;
 
-/** Wandelt einen Datenbank-Datensatz in die öffentliche Benutzer-Repräsentation um. */
-function toAuthUser(record: UserRecord): AuthUser {
-  return {
-    id: record.id,
-    username: record.username,
-    email: record.email,
-    displayName: record.displayName,
-    role: record.role,
-  };
-}
+const USER_FROM = `FROM users u JOIN roles r ON r.id = u.role_id`;
 
 /**
  * Benutzer-Repository (Infrastructure): Alle Datenbankzugriffe für Benutzer.
- * Enthält keine Business-Logik – nur Datenzugriff.
+ * Enthält keine Business-Logik – nur parametrisierten Datenzugriff.
  */
 @Injectable()
 export class UserRepository {
@@ -44,11 +35,17 @@ export class UserRepository {
     private readonly passwordHasher: PasswordHasher,
   ) {}
 
+  /** Alle Benutzer, neueste zuerst. */
+  async list(): Promise<UserRecord[]> {
+    const result = await this.database.query<UserRow>(
+      `SELECT ${USER_COLUMNS} ${USER_FROM} ORDER BY u.created_at DESC`,
+    );
+    return result.rows.map((row) => this.mapRow(row));
+  }
+
   async findByUsername(username: string): Promise<UserRecord | null> {
     const result = await this.database.query<UserRow>(
-      `SELECT ${USER_COLUMNS}
-         FROM users u JOIN roles r ON r.id = u.role_id
-        WHERE u.username = $1`,
+      `SELECT ${USER_COLUMNS} ${USER_FROM} WHERE u.username = $1`,
       [username],
     );
     return result.rows[0] ? this.mapRow(result.rows[0]) : null;
@@ -56,14 +53,104 @@ export class UserRepository {
 
   async findById(id: string): Promise<UserRecord | null> {
     const result = await this.database.query<UserRow>(
-      `SELECT ${USER_COLUMNS}
-         FROM users u JOIN roles r ON r.id = u.role_id
-        WHERE u.id = $1`,
+      `SELECT ${USER_COLUMNS} ${USER_FROM} WHERE u.id = $1`,
       [id],
     );
     return result.rows[0] ? this.mapRow(result.rows[0]) : null;
   }
 
+  async findByEmail(email: string): Promise<UserRecord | null> {
+    const result = await this.database.query<UserRow>(
+      `SELECT ${USER_COLUMNS} ${USER_FROM} WHERE u.email = $1`,
+      [email],
+    );
+    return result.rows[0] ? this.mapRow(result.rows[0]) : null;
+  }
+
+  /** Legt einen Benutzer an (Passwort wird gehasht). */
+  async create(input: CreateUserDto): Promise<UserRecord> {
+    const passwordHash = await this.passwordHasher.hash(input.password);
+    const result = await this.database.query<UserRow>(
+      `INSERT INTO users (username, email, password_hash, display_name, role_id)
+       VALUES ($1, $2, $3, $4, (SELECT id FROM roles WHERE name = $5))
+       RETURNING id, username, email, password_hash, display_name,
+                 (SELECT name FROM roles WHERE id = role_id) AS role_name,
+                 true AS is_active, 0 AS failed_login_attempts,
+                 NULL::timestamptz AS locked_until, NULL::timestamptz AS last_login_at,
+                 now() AS created_at, now() AS updated_at`,
+      [input.username, input.email, passwordHash, input.displayName, input.role],
+    );
+    return this.mapRow(result.rows[0]);
+  }
+
+  /** Aktualisiert nur die übergebenen Felder (dynamisch, parametrisiert). */
+  async update(id: string, changes: UpdateUserDto): Promise<UserRecord> {
+    const setClauses: string[] = [];
+    const params: unknown[] = [];
+    let parameterIndex = 1;
+
+    if (changes.email !== undefined) {
+      setClauses.push(`email = $${parameterIndex++}`);
+      params.push(changes.email);
+    }
+    if (changes.displayName !== undefined) {
+      setClauses.push(`display_name = $${parameterIndex++}`);
+      params.push(changes.displayName);
+    }
+    if (changes.role !== undefined) {
+      setClauses.push(`role_id = (SELECT id FROM roles WHERE name = $${parameterIndex++})`);
+      params.push(changes.role);
+    }
+    if (changes.isActive !== undefined) {
+      setClauses.push(`is_active = $${parameterIndex++}`);
+      params.push(changes.isActive);
+    }
+    setClauses.push('updated_at = now()');
+    params.push(id);
+
+    const result = await this.database.query<UserRow>(
+      `UPDATE users
+         SET ${setClauses.join(', ')}
+       WHERE id = $${parameterIndex}
+       RETURNING id, username, email, password_hash, display_name,
+                 (SELECT name FROM roles WHERE id = role_id) AS role_name,
+                 is_active, failed_login_attempts, locked_until,
+                 last_login_at, created_at, updated_at`,
+      params,
+    );
+    return this.mapRow(result.rows[0]);
+  }
+
+  /** Setzt einen neuen Passwort-Hash. */
+  async updatePassword(id: string, passwordHash: string): Promise<void> {
+    await this.database.query(
+      'UPDATE users SET password_hash = $2, updated_at = now() WHERE id = $1',
+      [id, passwordHash],
+    );
+  }
+
+  /** Setzt Fehlversuchs-Zähler und Sperre zurück (bei Aktivierung). */
+  async resetLoginLockout(id: string): Promise<void> {
+    await this.database.query(
+      'UPDATE users SET failed_login_attempts = 0, locked_until = NULL, updated_at = now() WHERE id = $1',
+      [id],
+    );
+  }
+
+  async delete(id: string): Promise<void> {
+    await this.database.query('DELETE FROM users WHERE id = $1', [id]);
+  }
+
+  /** Anzahl aktiver Administratoren (Schutz vor Verlust des letzten Admins). */
+  async countActiveAdmins(): Promise<number> {
+    const result = await this.database.query<{ count: number }>(
+      `SELECT count(*)::int AS count
+         FROM users u JOIN roles r ON r.id = u.role_id
+        WHERE r.name = 'ADMIN' AND u.is_active`,
+    );
+    return result.rows[0]?.count ?? 0;
+  }
+
   async updateLoginSuccess(userId: string): Promise<void> {
     await this.database.query(
       `UPDATE users
@@ -94,26 +181,6 @@ export class UserRepository {
     );
   }
 
-  async create(input: {
-    username: string;
-    email: string;
-    password: string;
-    displayName: string;
-    role: RoleName;
-  }): Promise<AuthUser> {
-    const passwordHash = await this.passwordHasher.hash(input.password);
-    const result = await this.database.query<UserRow>(
-      `INSERT INTO users (username, email, password_hash, display_name, role_id)
-       VALUES ($1, $2, $3, $4, (SELECT id FROM roles WHERE name = $5))
-       RETURNING id, username, email, display_name,
-                 (SELECT name FROM roles WHERE id = role_id) AS role_name,
-                 true AS is_active, 0 AS failed_login_attempts, NULL::timestamptz AS locked_until,
-                 NULL::timestamptz AS last_login_at, now() AS created_at, now() AS updated_at`,
-      [input.username, input.email, passwordHash, input.displayName, input.role],
-    );
-    return toAuthUser(this.mapRow(result.rows[0]));
-  }
-
   private mapRow(row: UserRow): UserRecord {
     return {
       id: row.id,

apps/platform-backend/src/users/user.types.ts

@@ -30,3 +30,47 @@ export const loginSchema = z.object({
   password: z.string().min(1).max(200),
 });
 export type LoginDto = z.infer<typeof loginSchema>;
+
+/** Erlaubte Zeichen für Benutzernamen (kein Whitespace, keine Sonderzeichen). */
+const USERNAME_PATTERN = /^[A-Za-z0-9._-]+$/;
+
+/** Benutzer anlegen (Admin). */
+export const createUserSchema = z.object({
+  username: z
+    .string()
+    .trim()
+    .min(3, 'Benutzername muss mindestens 3 Zeichen lang sein')
+    .max(100)
+    .regex(USERNAME_PATTERN, 'Benutzername darf nur Buchstaben, Zahlen sowie . _ - enthalten'),
+  email: z.string().trim().email('Ungültige E-Mail-Adresse').max(255),
+  displayName: z.string().trim().min(1, 'Anzeigename ist erforderlich').max(200),
+  password: z.string().min(10, 'Passwort muss mindestens 10 Zeichen lang sein').max(200),
+  role: z.enum(ROLE_NAMES),
+});
+export type CreateUserDto = z.infer<typeof createUserSchema>;
+
+/** Benutzer bearbeiten (Admin) – mindestens ein Feld muss gesetzt sein. */
+export const updateUserSchema = z
+  .object({
+    email: z.string().trim().email('Ungültige E-Mail-Adresse').max(255).optional(),
+    displayName: z.string().trim().min(1, 'Anzeigename ist erforderlich').max(200).optional(),
+    role: z.enum(ROLE_NAMES).optional(),
+    isActive: z.boolean().optional(),
+  })
+  .refine((data) => Object.values(data).some((value) => value !== undefined), {
+    message: 'Mindestens ein Feld ist erforderlich',
+  });
+export type UpdateUserDto = z.infer<typeof updateUserSchema>;
+
+/** Passwort durch einen Administrator zurücksetzen. */
+export const resetPasswordSchema = z.object({
+  newPassword: z.string().min(10, 'Passwort muss mindestens 10 Zeichen lang sein').max(200),
+});
+export type ResetPasswordDto = z.infer<typeof resetPasswordSchema>;
+
+/** Eigenes Passwort ändern (angemeldeter Benutzer). */
+export const changePasswordSchema = z.object({
+  currentPassword: z.string().min(1, 'Aktuelles Passwort ist erforderlich').max(200),
+  newPassword: z.string().min(10, 'Passwort muss mindestens 10 Zeichen lang sein').max(200),
+});
+export type ChangePasswordDto = z.infer<typeof changePasswordSchema>;

apps/platform-backend/src/users/users.controller.ts

@@ -0,0 +1,118 @@
+import {
+  Body,
+  Controller,
+  Delete,
+  Get,
+  Param,
+  ParseUUIDPipe,
+  Patch,
+  Post,
+  Req,
+} from '@nestjs/common';
+import type { Request } from 'express';
+import { ApiTags } from '@nestjs/swagger';
+import type { AuthenticatedRequest } from '../auth/authenticated-request';
+import { CurrentUser } from '../common/decorators/current-user.decorator';
+import { Roles } from '../common/decorators/roles.decorator';
+import { ZodValidationPipe } from '../common/zod-validation.pipe';
+import type { AuthUser, RoleName, UserRecord } from './user.types';
+import {
+  createUserSchema,
+  resetPasswordSchema,
+  updateUserSchema,
+  type CreateUserDto,
+  type ResetPasswordDto,
+  type UpdateUserDto,
+} from './user.types';
+import { UsersService } from './users.service';
+
+/** Benutzerdaten in API-Antworten (ohne interne Felder). */
+interface UserResponse {
+  id: string;
+  username: string;
+  email: string;
+  displayName: string;
+  role: RoleName;
+  isActive: boolean;
+  lastLoginAt: string | null;
+  createdAt: string;
+}
+
+function toUserResponse(user: UserRecord): UserResponse {
+  return {
+    id: user.id,
+    username: user.username,
+    email: user.email,
+    displayName: user.displayName,
+    role: user.role,
+    isActive: user.isActive,
+    lastLoginAt: user.lastLoginAt ? user.lastLoginAt.toISOString() : null,
+    createdAt: user.createdAt.toISOString(),
+  };
+}
+
+/**
+ * Benutzerverwaltung (nur Administratoren).
+ * Guards (Session, CSRF, Rollen) sind global registriert;
+ * @Roles('ADMIN') erzwingt die Administrator-Rolle auf Klassenebene.
+ */
+@ApiTags('Users')
+@Roles('ADMIN')
+@Controller({ path: 'api/v1/users' })
+export class UsersController {
+  constructor(private readonly usersService: UsersService) {}
+
+  @Get()
+  async list(): Promise<{ users: UserResponse[] }> {
+    const users = await this.usersService.list();
+    return { users: users.map(toUserResponse) };
+  }
+
+  @Post()
+  async create(
+    @Body(new ZodValidationPipe(createUserSchema)) body: CreateUserDto,
+    @CurrentUser() actor: AuthUser,
+    @Req() request: AuthenticatedRequest & Request,
+  ): Promise<{ user: UserResponse }> {
+    const user = await this.usersService.create(body, actor, request.ip ?? null);
+    return { user: toUserResponse(user) };
+  }
+
+  @Get(':id')
+  async getById(@Param('id', ParseUUIDPipe) id: string): Promise<{ user: UserResponse }> {
+    const user = await this.usersService.findById(id);
+    return { user: toUserResponse(user) };
+  }
+
+  @Patch(':id/password')
+  async resetPassword(
+    @Param('id', ParseUUIDPipe) id: string,
+    @Body(new ZodValidationPipe(resetPasswordSchema)) body: ResetPasswordDto,
+    @CurrentUser() actor: AuthUser,
+    @Req() request: AuthenticatedRequest & Request,
+  ): Promise<{ success: true }> {
+    await this.usersService.resetPassword(id, body, actor, request.ip ?? null);
+    return { success: true };
+  }
+
+  @Patch(':id')
+  async update(
+    @Param('id', ParseUUIDPipe) id: string,
+    @Body(new ZodValidationPipe(updateUserSchema)) body: UpdateUserDto,
+    @CurrentUser() actor: AuthUser,
+    @Req() request: AuthenticatedRequest & Request,
+  ): Promise<{ user: UserResponse }> {
+    const user = await this.usersService.update(id, body, actor, request.ip ?? null);
+    return { user: toUserResponse(user) };
+  }
+
+  @Delete(':id')
+  async remove(
+    @Param('id', ParseUUIDPipe) id: string,
+    @CurrentUser() actor: AuthUser,
+    @Req() request: AuthenticatedRequest & Request,
+  ): Promise<{ success: true }> {
+    await this.usersService.remove(id, actor, request.ip ?? null);
+    return { success: true };
+  }
+}

apps/platform-backend/src/users/users.module.ts

@@ -1,14 +1,21 @@
 import { Module } from '@nestjs/common';
 import { ConfigModule } from '../config/config.module';
 import { DatabaseModule } from '../database/database.module';
+import { AuditModule } from '../audit/audit.module';
+import { SessionService } from '../auth/session.service';
 import { PasswordHasher } from './password-hasher';
+import { ProfileController } from './profile.controller';
+import { ProfileService } from './profile.service';
 import { SeedService } from './seed.service';
 import { UserRepository } from './user.repository';
+import { UsersController } from './users.controller';
+import { UsersService } from './users.service';
 
-/** Benutzerverwaltung (Phase 1: Modell, Rollen, Seed). */
+/** Benutzerverwaltung: Admin-API, Profil, Rollen, Seed. */
 @Module({
-  imports: [ConfigModule, DatabaseModule],
-  providers: [UserRepository, PasswordHasher, SeedService],
+  imports: [ConfigModule, DatabaseModule, AuditModule],
+  controllers: [UsersController, ProfileController],
+  providers: [UserRepository, PasswordHasher, SeedService, UsersService, ProfileService, SessionService],
   exports: [UserRepository, PasswordHasher],
 })
 export class UsersModule {}

apps/platform-backend/src/users/users.service.spec.ts

@@ -0,0 +1,253 @@
+import { BadRequestException, ConflictException, NotFoundException } from '@nestjs/common';
+import { AUDIT_ACTIONS, AuditService } from '../audit/audit.service';
+import { SessionService } from '../auth/session.service';
+import { PasswordHasher } from './password-hasher';
+import { UserRepository } from './user.repository';
+import type { CreateUserDto, UserRecord } from './user.types';
+import { UsersService, type ActingUser } from './users.service';
+
+/** Erzeugt einen Benutzer-Datensatz für Tests. */
+function createUserRecord(overrides: Partial<UserRecord> = {}): UserRecord {
+  return {
+    id: 'user-1',
+    username: 'max',
+    email: 'max@example.com',
+    passwordHash: 'not-a-real-hash',
+    displayName: 'Max Mustermann',
+    role: 'USER',
+    isActive: true,
+    failedLoginAttempts: 0,
+    lockedUntil: null,
+    lastLoginAt: null,
+    createdAt: new Date(),
+    updatedAt: new Date(),
+    ...overrides,
+  };
+}
+
+const ACTOR: ActingUser = { id: 'admin-1', username: 'admin' };
+
+/** Mock des UserRepository. */
+class MockUserRepository {
+  public users: UserRecord[] = [createUserRecord()];
+  public deletedIds: string[] = [];
+  public updatedPasswords: Array<{ id: string; hash: string }> = [];
+  public lockoutResets: string[] = [];
+
+  async list(): Promise<UserRecord[]> {
+    return this.users;
+  }
+
+  async findById(id: string): Promise<UserRecord | null> {
+    return this.users.find((user) => user.id === id) ?? null;
+  }
+
+  async findByUsername(username: string): Promise<UserRecord | null> {
+    return this.users.find((user) => user.username === username) ?? null;
+  }
+
+  async findByEmail(email: string): Promise<UserRecord | null> {
+    return this.users.find((user) => user.email === email) ?? null;
+  }
+
+  async create(input: CreateUserDto): Promise<UserRecord> {
+    const user = createUserRecord({
+      id: 'new-user',
+      username: input.username,
+      email: input.email,
+      displayName: input.displayName,
+      role: input.role,
+    });
+    this.users.push(user);
+    return user;
+  }
+
+  async update(id: string, changes: Partial<UserRecord>): Promise<UserRecord> {
+    const index = this.users.findIndex((user) => user.id === id);
+    if (index === -1) {
+      throw new Error('nicht gefunden');
+    }
+    this.users[index] = { ...this.users[index], ...changes };
+    return this.users[index];
+  }
+
+  async updatePassword(id: string, hash: string): Promise<void> {
+    this.updatedPasswords.push({ id, hash });
+  }
+
+  async resetLoginLockout(id: string): Promise<void> {
+    this.lockoutResets.push(id);
+  }
+
+  async delete(id: string): Promise<void> {
+    this.deletedIds.push(id);
+    this.users = this.users.filter((user) => user.id !== id);
+  }
+
+  async countActiveAdmins(): Promise<number> {
+    return this.users.filter((user) => user.role === 'ADMIN' && user.isActive).length;
+  }
+}
+
+/** Mock des SessionService. */
+class MockSessionService {
+  public deletedSessionsForUser: string[] = [];
+
+  async deleteAllForUser(userId: string): Promise<void> {
+    this.deletedSessionsForUser.push(userId);
+  }
+}
+
+/** Mock des AuditService. */
+class MockAuditService {
+  public records: Array<{ action: string; userId: string | null }> = [];
+
+  async record(entry: { action: string; userId: string | null }): Promise<void> {
+    this.records.push(entry);
+  }
+}
+
+describe('UsersService', () => {
+  let userRepository: MockUserRepository;
+  let sessionService: MockSessionService;
+  let auditService: MockAuditService;
+  let usersService: UsersService;
+  let passwordHasher: PasswordHasher;
+
+  const createUserInput: CreateUserDto = {
+    username: 'neu',
+    email: 'neu@example.com',
+    displayName: 'Neuer Benutzer',
+    password: 'Sicheres-Passwort-1',
+    role: 'USER',
+  };
+
+  beforeEach(() => {
+    userRepository = new MockUserRepository();
+    sessionService = new MockSessionService();
+    auditService = new MockAuditService();
+    passwordHasher = new PasswordHasher();
+    usersService = new UsersService(
+      userRepository as unknown as UserRepository,
+      passwordHasher,
+      sessionService as unknown as SessionService,
+      auditService as unknown as AuditService,
+    );
+  });
+
+  describe('list', () => {
+    it('gibt alle Benutzer zurück', async () => {
+      const users = await usersService.list();
+      expect(users).toHaveLength(1);
+      expect(users[0].username).toBe('max');
+    });
+  });
+
+  describe('findById', () => {
+    it('wirft NotFoundException bei unbekannter ID', async () => {
+      await expect(usersService.findById('unbekannt')).rejects.toThrow(NotFoundException);
+    });
+  });
+
+  describe('create', () => {
+    it('legt einen neuen Benutzer an und schreibt Audit', async () => {
+      const user = await usersService.create(createUserInput, ACTOR, '127.0.0.1');
+      expect(user.username).toBe('neu');
+      expect(auditService.records.at(-1)?.action).toBe(AUDIT_ACTIONS.USER_CREATED);
+    });
+
+    it('lehnt doppelte Benutzernamen ab', async () => {
+      await expect(
+        usersService.create({ ...createUserInput, username: 'max' }, ACTOR, null),
+      ).rejects.toThrow(ConflictException);
+    });
+
+    it('lehnt doppelte E-Mail-Adressen ab', async () => {
+      await expect(
+        usersService.create({ ...createUserInput, email: 'max@example.com' }, ACTOR, null),
+      ).rejects.toThrow(ConflictException);
+    });
+  });
+
+  describe('update', () => {
+    it('aktualisiert den Anzeigenamen und schreibt Audit', async () => {
+      const updated = await usersService.update(
+        'user-1',
+        { displayName: 'Max M.' },
+        ACTOR,
+        null,
+      );
+      expect(updated.displayName).toBe('Max M.');
+      expect(auditService.records.at(-1)?.action).toBe(AUDIT_ACTIONS.USER_UPDATED);
+    });
+
+    it('verhindert Selbst-Deaktivierung', async () => {
+      userRepository.users[0] = createUserRecord({ id: 'admin-1', role: 'ADMIN' });
+      await expect(
+        usersService.update('admin-1', { isActive: false }, ACTOR, null),
+      ).rejects.toThrow(BadRequestException);
+    });
+
+    it('meldet deaktivierte Benutzer von allen Sessions ab', async () => {
+      await usersService.update('user-1', { isActive: false }, ACTOR, null);
+      expect(sessionService.deletedSessionsForUser).toEqual(['user-1']);
+      expect(auditService.records.at(-1)?.action).toBe(AUDIT_ACTIONS.USER_DISABLED);
+    });
+
+    it('setzt Login-Sperre bei Reaktivierung zurück', async () => {
+      userRepository.users[0] = createUserRecord({ isActive: false });
+      await usersService.update('user-1', { isActive: true }, ACTOR, null);
+      expect(userRepository.lockoutResets).toEqual(['user-1']);
+      expect(auditService.records.at(-1)?.action).toBe(AUDIT_ACTIONS.USER_ENABLED);
+    });
+
+    it('verhindert die Deaktivierung des letzten aktiven Admins', async () => {
+      userRepository.users[0] = createUserRecord({ id: 'admin-1', role: 'ADMIN' });
+      await expect(
+        usersService.update('admin-1', { isActive: false }, { id: 'anderer', username: 'x' }, null),
+      ).rejects.toThrow(BadRequestException);
+    });
+
+    it('verhindert die Herabstufung des letzten aktiven Admins', async () => {
+      userRepository.users[0] = createUserRecord({ id: 'admin-1', role: 'ADMIN' });
+      await expect(
+        usersService.update('admin-1', { role: 'USER' }, { id: 'anderer', username: 'x' }, null),
+      ).rejects.toThrow(BadRequestException);
+    });
+  });
+
+  describe('resetPassword', () => {
+    it('setzt das Passwort, meldet Sessions ab und schreibt Audit', async () => {
+      await usersService.resetPassword(
+        'user-1',
+        { newPassword: 'Neues-Passwort-123' },
+        ACTOR,
+        null,
+      );
+      expect(userRepository.updatedPasswords).toHaveLength(1);
+      expect(sessionService.deletedSessionsForUser).toEqual(['user-1']);
+      expect(auditService.records.at(-1)?.action).toBe(AUDIT_ACTIONS.USER_PASSWORD_RESET);
+    });
+  });
+
+  describe('remove', () => {
+    it('löscht einen Benutzer und schreibt Audit', async () => {
+      await usersService.remove('user-1', ACTOR, null);
+      expect(userRepository.deletedIds).toEqual(['user-1']);
+      expect(auditService.records.at(-1)?.action).toBe(AUDIT_ACTIONS.USER_DELETED);
+    });
+
+    it('verhindert Selbst-Löschung', async () => {
+      await expect(usersService.remove('admin-1', ACTOR, null)).rejects.toThrow(
+        BadRequestException,
+      );
+    });
+
+    it('verhindert die Löschung des letzten aktiven Admins', async () => {
+      userRepository.users[0] = createUserRecord({ id: 'admin-1', role: 'ADMIN' });
+      await expect(
+        usersService.remove('admin-1', { id: 'anderer', username: 'x' }, null),
+      ).rejects.toThrow(BadRequestException);
+    });
+  });
+});

apps/platform-backend/src/users/users.service.ts

@@ -0,0 +1,174 @@
+import {
+  BadRequestException,
+  ConflictException,
+  Injectable,
+  NotFoundException,
+} from '@nestjs/common';
+import { AUDIT_ACTIONS, AuditService, type AuditAction } from '../audit/audit.service';
+import { SessionService } from '../auth/session.service';
+import { PasswordHasher } from './password-hasher';
+import { UserRepository } from './user.repository';
+import type { CreateUserDto, ResetPasswordDto, UpdateUserDto, UserRecord } from './user.types';
+
+/** Der handelnde Benutzer (für Audit-Einträge). */
+export interface ActingUser {
+  readonly id: string;
+  readonly username: string;
+}
+
+/**
+ * Benutzerverwaltung (Application-Layer): Business-Regeln für Anlegen,
+ * Bearbeiten, Aktivieren/Deaktivieren und Löschen von Benutzern.
+ *
+ * Schutzregeln:
+ * - Keine Selbst-Deaktivierung und keine Selbst-Löschung
+ * - Der letzte aktive Administrator kann nicht herabgestuft,
+ *   deaktiviert oder gelöscht werden
+ * - Deaktivierte Benutzer werden sofort von allen Sessions abgemeldet
+ */
+@Injectable()
+export class UsersService {
+  constructor(
+    private readonly userRepository: UserRepository,
+    private readonly passwordHasher: PasswordHasher,
+    private readonly sessionService: SessionService,
+    private readonly auditService: AuditService,
+  ) {}
+
+  async list(): Promise<UserRecord[]> {
+    return this.userRepository.list();
+  }
+
+  async findById(id: string): Promise<UserRecord> {
+    const user = await this.userRepository.findById(id);
+    if (!user) {
+      throw new NotFoundException('Benutzer nicht gefunden');
+    }
+    return user;
+  }
+
+  async create(
+    input: CreateUserDto,
+    actor: ActingUser,
+    ipAddress: string | null,
+  ): Promise<UserRecord> {
+    const [existingUsername, existingEmail] = await Promise.all([
+      this.userRepository.findByUsername(input.username),
+      this.userRepository.findByEmail(input.email),
+    ]);
+    if (existingUsername) {
+      throw new ConflictException('Benutzername ist bereits vergeben');
+    }
+    if (existingEmail) {
+      throw new ConflictException('E-Mail-Adresse ist bereits vergeben');
+    }
+
+    const user = await this.userRepository.create(input);
+    await this.auditService.record({
+      userId: actor.id,
+      username: actor.username,
+      action: AUDIT_ACTIONS.USER_CREATED,
+      details: { targetUserId: user.id, targetUsername: user.username, role: user.role },
+      ipAddress,
+    });
+    return user;
+  }
+
+  async update(
+    id: string,
+    input: UpdateUserDto,
+    actor: ActingUser,
+    ipAddress: string | null,
+  ): Promise<UserRecord> {
+    const user = await this.findById(id);
+
+    if (input.email !== undefined && input.email !== user.email) {
+      const existingEmail = await this.userRepository.findByEmail(input.email);
+      if (existingEmail && existingEmail.id !== id) {
+        throw new ConflictException('E-Mail-Adresse ist bereits vergeben');
+      }
+    }
+
+    const demotesFromAdmin = user.role === 'ADMIN' && input.role === 'USER';
+    const deactivates = input.isActive === false && user.isActive;
+    const activates = input.isActive === true && !user.isActive;
+
+    if (deactivates && id === actor.id) {
+      throw new BadRequestException('Sie können Ihr eigenes Konto nicht deaktivieren');
+    }
+    if ((demotesFromAdmin || deactivates) && (await this.isLastActiveAdmin(user))) {
+      throw new BadRequestException(
+        'Der letzte aktive Administrator kann nicht herabgestuft oder deaktiviert werden',
+      );
+    }
+
+    const updated = await this.userRepository.update(id, input);
+
+    if (deactivates) {
+      await this.sessionService.deleteAllForUser(id);
+    }
+    if (activates) {
+      await this.userRepository.resetLoginLockout(id);
+    }
+
+    const action: AuditAction = deactivates
+      ? AUDIT_ACTIONS.USER_DISABLED
+      : activates
+        ? AUDIT_ACTIONS.USER_ENABLED
+        : AUDIT_ACTIONS.USER_UPDATED;
+    await this.auditService.record({
+      userId: actor.id,
+      username: actor.username,
+      action,
+      details: { targetUserId: id, targetUsername: user.username },
+      ipAddress,
+    });
+    return updated;
+  }
+
+  async resetPassword(
+    id: string,
+    input: ResetPasswordDto,
+    actor: ActingUser,
+    ipAddress: string | null,
+  ): Promise<void> {
+    const user = await this.findById(id);
+    const passwordHash = await this.passwordHasher.hash(input.newPassword);
+    await this.userRepository.updatePassword(id, passwordHash);
+    await this.sessionService.deleteAllForUser(id);
+    await this.auditService.record({
+      userId: actor.id,
+      username: actor.username,
+      action: AUDIT_ACTIONS.USER_PASSWORD_RESET,
+      details: { targetUserId: id, targetUsername: user.username },
+      ipAddress,
+    });
+  }
+
+  async remove(id: string, actor: ActingUser, ipAddress: string | null): Promise<void> {
+    if (id === actor.id) {
+      throw new BadRequestException('Sie können Ihr eigenes Konto nicht löschen');
+    }
+    const user = await this.findById(id);
+    if (await this.isLastActiveAdmin(user)) {
+      throw new BadRequestException('Der letzte aktive Administrator kann nicht gelöscht werden');
+    }
+    await this.userRepository.delete(id);
+    await this.auditService.record({
+      userId: actor.id,
+      username: actor.username,
+      action: AUDIT_ACTIONS.USER_DELETED,
+      details: { targetUserId: id, targetUsername: user.username },
+      ipAddress,
+    });
+  }
+
+  /** Prüft, ob der gegebene Benutzer der einzige aktive Administrator ist. */
+  private async isLastActiveAdmin(user: UserRecord): Promise<boolean> {
+    if (user.role !== 'ADMIN' || !user.isActive) {
+      return false;
+    }
+    const activeAdminCount = await this.userRepository.countActiveAdmins();
+    return activeAdminCount <= 1;
+  }
+}

apps/platform-frontend/src/components/layout/app-layout.tsx

@@ -13,6 +13,7 @@ interface NavItem {
 
 const NAV_ITEMS: NavItem[] = [
   { to: '/', label: 'Dashboard', icon: '⌂' },
+  { to: '/profile', label: 'Mein Profil', icon: '👤' },
   { to: '/admin/users', label: 'Benutzer', icon: '👥', adminOnly: true },
   { to: '/admin/system', label: 'Systemstatus', icon: '⚙', adminOnly: true },
 ];

apps/platform-frontend/src/components/ui/modal.tsx

@@ -0,0 +1,60 @@
+import { type ReactNode, useEffect } from 'react';
+
+export interface ModalProps {
+  open: boolean;
+  title: string;
+  description?: string;
+  onClose: () => void;
+  children: ReactNode;
+  footer?: ReactNode;
+}
+
+/** Zugängliches Modal (Design-System): Fokus-Falle, ESC schließt. */
+export function Modal({
+  open,
+  title,
+  description,
+  onClose,
+  children,
+  footer,
+}: ModalProps): ReactNode {
+  useEffect(() => {
+    if (!open) {
+      return undefined;
+    }
+    const handleKeyDown = (event: KeyboardEvent): void => {
+      if (event.key === 'Escape') {
+        onClose();
+      }
+    };
+    document.addEventListener('keydown', handleKeyDown);
+    return () => document.removeEventListener('keydown', handleKeyDown);
+  }, [open, onClose]);
+
+  if (!open) {
+    return null;
+  }
+
+  return (
+    <div
+      className="fixed inset-0 z-50 flex items-center justify-center bg-slate-900/50 p-4"
+      onClick={onClose}
+      role="presentation"
+    >
+      <div
+        role="dialog"
+        aria-modal="true"
+        aria-label={title}
+        className="w-full max-w-md rounded-xl bg-white shadow-xl"
+        onClick={(event) => event.stopPropagation()}
+      >
+        <div className="border-b border-slate-200 px-6 py-4">
+          <h2 className="text-base font-semibold text-slate-900">{title}</h2>
+          {description && <p className="mt-0.5 text-sm text-slate-500">{description}</p>}
+        </div>
+        <div className="px-6 py-4">{children}</div>
+        {footer && <div className="border-t border-slate-200 px-6 py-4">{footer}</div>}
+      </div>
+    </div>
+  );
+}

apps/platform-frontend/src/components/ui/select.tsx

@@ -0,0 +1,50 @@
+import { type ReactNode, type SelectHTMLAttributes } from 'react';
+
+export interface SelectProps extends SelectHTMLAttributes<HTMLSelectElement> {
+  label: string;
+  error?: string;
+  options: ReadonlyArray<{ value: string; label: string }>;
+}
+
+/** Select-Dropdown mit Label (Design-System). */
+export function Select({
+  label,
+  error,
+  options,
+  className = '',
+  id,
+  ...rest
+}: SelectProps): ReactNode {
+  const selectId = id ?? `select-${label.toLowerCase().replace(/\s+/g, '-')}`;
+
+  return (
+    <div className="flex flex-col gap-1.5">
+      <label htmlFor={selectId} className="text-sm font-medium text-slate-700">
+        {label}
+      </label>
+      <select
+        id={selectId}
+        className={`h-10 rounded-lg border bg-white px-3 text-sm transition-colors
+          ${
+            error
+              ? 'border-red-400 focus:border-red-500'
+              : 'border-slate-300 focus:border-brand-500'
+          }
+          ${className}`}
+        aria-invalid={error ? true : undefined}
+        {...rest}
+      >
+        {options.map((option) => (
+          <option key={option.value} value={option.value}>
+            {option.label}
+          </option>
+        ))}
+      </select>
+      {error && (
+        <p role="alert" className="text-xs text-red-600">
+          {error}
+        </p>
+      )}
+    </div>
+  );
+}

apps/platform-frontend/src/components/ui/toast.tsx

@@ -0,0 +1,84 @@
+import {
+  type ReactNode,
+  createContext,
+  useCallback,
+  useContext,
+  useMemo,
+  useRef,
+  useState,
+} from 'react';
+
+/** Toast-Varianten. */
+export type ToastVariant = 'success' | 'error';
+
+interface ToastEntry {
+  readonly id: number;
+  readonly variant: ToastVariant;
+  readonly message: string;
+}
+
+interface ToastContextValue {
+  showToast: (variant: ToastVariant, message: string) => void;
+}
+
+const ToastContext = createContext<ToastContextValue | null>(null);
+
+const VARIANT_CLASSES: Record<ToastVariant, string> = {
+  success: 'bg-emerald-600 text-white',
+  error: 'bg-red-600 text-white',
+};
+
+const VARIANT_ICONS: Record<ToastVariant, string> = {
+  success: '✓',
+  error: '✕',
+};
+
+/**
+ * Toast-Benachrichtigungen (Design-System).
+ * Meldungen verschwinden automatisch nach 4 Sekunden.
+ */
+export function ToastProvider({ children }: { children: ReactNode }): ReactNode {
+  const [toasts, setToasts] = useState<ToastEntry[]>([]);
+  const nextId = useRef(1);
+
+  const showToast = useCallback((variant: ToastVariant, message: string) => {
+    const id = nextId.current;
+    nextId.current += 1;
+    setToasts((current) => [...current, { id, variant, message }]);
+    window.setTimeout(() => {
+      setToasts((current) => current.filter((toast) => toast.id !== id));
+    }, 4_000);
+  }, []);
+
+  const value = useMemo<ToastContextValue>(() => ({ showToast }), [showToast]);
+
+  return (
+    <ToastContext.Provider value={value}>
+      {children}
+      <div
+        className="pointer-events-none fixed bottom-4 right-4 z-50 flex flex-col gap-2"
+        aria-live="polite"
+      >
+        {toasts.map((toast) => (
+          <div
+            key={toast.id}
+            className={`pointer-events-auto flex items-center gap-2 rounded-lg px-4 py-3 text-sm font-medium shadow-lg
+              ${VARIANT_CLASSES[toast.variant]}`}
+          >
+            <span aria-hidden="true">{VARIANT_ICONS[toast.variant]}</span>
+            {toast.message}
+          </div>
+        ))}
+      </div>
+    </ToastContext.Provider>
+  );
+}
+
+/** Zeigt eine Toast-Meldung an (wirft außerhalb des Providers). */
+export function useToast(): ToastContextValue {
+  const context = useContext(ToastContext);
+  if (!context) {
+    throw new Error('useToast muss innerhalb von ToastProvider verwendet werden');
+  }
+  return context;
+}

apps/platform-frontend/src/features/admin/users-page.tsx

@@ -1,28 +1,516 @@
-import { type ReactNode } from 'react';
-import { Card, CardBody, CardHeader } from '../../components/ui/card';
-import { EmptyState } from '../../components/ui/states';
+import { type FormEvent, type ReactNode, useState } from 'react';
+import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
+import { useAuth } from '../auth/auth-context';
+import { Button } from '../../components/ui/button';
+import { Input } from '../../components/ui/input';
+import { Modal } from '../../components/ui/modal';
+import { Select } from '../../components/ui/select';
+import { useToast } from '../../components/ui/toast';
+import { ApiError } from '../../lib/api-client';
+import {
+  createUser,
+  deleteUser,
+  fetchUsers,
+  resetUserPassword,
+  updateUser,
+} from '../../lib/users-api';
+import {
+  createUserSchema,
+  resetPasswordSchema,
+  ROLE_NAMES,
+  type RoleName,
+  type User,
+} from '../../lib/schemas';
 
-/** Platzhalter für die Benutzerverwaltung (Phase 2). */
+/** Formular-Fehler aus Zod-Issues (nur erste Meldung pro Feld). */
+function fieldErrorsFromZod(
+  issues: Array<{ path: (string | number | symbol)[]; message: string }>,
+): Record<string, string> {
+  const errors: Record<string, string> = {};
+  for (const issue of issues) {
+    const key = String(issue.path[0] ?? 'form');
+    if (!errors[key]) {
+      errors[key] = issue.message;
+    }
+  }
+  return errors;
+}
+
+/** API-Fehler-Details in einfache Feldmeldungen umwandeln. */
+function fieldErrorsFromApi(details: Record<string, string | string[]> | undefined): Record<string, string> {
+  if (!details) {
+    return {};
+  }
+  const errors: Record<string, string> = {};
+  for (const [key, value] of Object.entries(details)) {
+    errors[key] = Array.isArray(value) ? value[0] : value;
+  }
+  return errors;
+}
+
+/** Datumsformat für Tabellenanzeigen. */
+function formatDate(isoDate: string | null): string {
+  if (!isoDate) {
+    return '–';
+  }
+  return new Date(isoDate).toLocaleDateString('de-DE', {
+    day: '2-digit',
+    month: '2-digit',
+    year: 'numeric',
+    hour: '2-digit',
+    minute: '2-digit',
+  });
+}
+
+/** Formular: Neuen Benutzer anlegen. */
+function CreateUserModal({
+  open,
+  onClose,
+  onCreated,
+}: {
+  open: boolean;
+  onClose: () => void;
+  onCreated: () => void;
+}): ReactNode {
+  const { showToast } = useToast();
+  const [fieldErrors, setFieldErrors] = useState<Record<string, string>>({});
+  const [formError, setFormError] = useState<string | null>(null);
+
+  const createMutation = useMutation({
+    mutationFn: createUser,
+    onSuccess: (user) => {
+      showToast('success', `Benutzer "${user.username}" wurde angelegt`);
+      onCreated();
+      onClose();
+    },
+    onError: (error) => {
+      if (error instanceof ApiError) {
+        setFormError(error.message);
+        setFieldErrors(fieldErrorsFromApi(error.details));
+      } else {
+        setFormError('Benutzer konnte nicht angelegt werden');
+      }
+    },
+  });
+
+  function handleSubmit(event: FormEvent<HTMLFormElement>): void {
+    event.preventDefault();
+    setFieldErrors({});
+    setFormError(null);
+
+    const formData = new FormData(event.currentTarget);
+    const parsed = createUserSchema.safeParse({
+      username: formData.get('username'),
+      email: formData.get('email'),
+      displayName: formData.get('displayName'),
+      password: formData.get('password'),
+      role: formData.get('role'),
+    });
+    if (!parsed.success) {
+      setFieldErrors(fieldErrorsFromZod(parsed.error.issues));
+      return;
+    }
+    createMutation.mutate(parsed.data);
+  }
+
+  return (
+    <Modal
+      open={open}
+      title="Benutzer anlegen"
+      description="Neuen Benutzer für die Plattform registrieren"
+      onClose={onClose}
+    >
+      <form onSubmit={handleSubmit} className="space-y-4" noValidate>
+        <Input label="Benutzername" name="username" error={fieldErrors.username} autoFocus />
+        <Input label="Anzeigename" name="displayName" error={fieldErrors.displayName} />
+        <Input label="E-Mail-Adresse" name="email" type="email" error={fieldErrors.email} />
+        <Input
+          label="Passwort"
+          name="password"
+          type="password"
+          hint="Mindestens 10 Zeichen"
+          error={fieldErrors.password}
+        />
+        <Select
+          label="Rolle"
+          name="role"
+          defaultValue="USER"
+          error={fieldErrors.role}
+          options={ROLE_NAMES.map((role) => ({
+            value: role,
+            label: role === 'ADMIN' ? 'Administrator' : 'Benutzer',
+          }))}
+        />
+        {formError && (
+          <p role="alert" className="rounded-lg bg-red-50 px-3 py-2 text-sm text-red-700">
+            {formError}
+          </p>
+        )}
+        <div className="flex justify-end gap-2 pt-2">
+          <Button type="button" variant="secondary" onClick={onClose}>
+            Abbrechen
+          </Button>
+          <Button type="submit" loading={createMutation.isPending}>
+            Anlegen
+          </Button>
+        </div>
+      </form>
+    </Modal>
+  );
+}
+
+/** Formular: Benutzer bearbeiten. */
+function EditUserModal({ user, onClose }: { user: User; onClose: () => void }): ReactNode {
+  const { showToast } = useToast();
+  const queryClient = useQueryClient();
+  const [fieldErrors, setFieldErrors] = useState<Record<string, string>>({});
+  const [formError, setFormError] = useState<string | null>(null);
+
+  const updateMutation = useMutation({
+    mutationFn: (input: { email: string; displayName: string; role: RoleName }) =>
+      updateUser(user.id, input),
+    onSuccess: () => {
+      void queryClient.invalidateQueries({ queryKey: ['users'] });
+      showToast('success', 'Benutzer wurde gespeichert');
+      onClose();
+    },
+    onError: (error) => {
+      if (error instanceof ApiError) {
+        setFormError(error.message);
+        setFieldErrors(fieldErrorsFromApi(error.details));
+      } else {
+        setFormError('Benutzer konnte nicht gespeichert werden');
+      }
+    },
+  });
+
+  function handleSubmit(event: FormEvent<HTMLFormElement>): void {
+    event.preventDefault();
+    setFieldErrors({});
+    setFormError(null);
+
+    const formData = new FormData(event.currentTarget);
+    const role = String(formData.get('role'));
+    updateMutation.mutate({
+      email: String(formData.get('email')),
+      displayName: String(formData.get('displayName')),
+      role: role === 'ADMIN' ? 'ADMIN' : 'USER',
+    });
+  }
+
+  return (
+    <Modal open title="Benutzer bearbeiten" description={`@${user.username}`} onClose={onClose}>
+      <form onSubmit={handleSubmit} className="space-y-4" noValidate>
+        <Input
+          label="Anzeigename"
+          name="displayName"
+          defaultValue={user.displayName}
+          error={fieldErrors.displayName}
+          autoFocus
+        />
+        <Input
+          label="E-Mail-Adresse"
+          name="email"
+          type="email"
+          defaultValue={user.email}
+          error={fieldErrors.email}
+        />
+        <Select
+          label="Rolle"
+          name="role"
+          defaultValue={user.role}
+          error={fieldErrors.role}
+          options={ROLE_NAMES.map((role) => ({
+            value: role,
+            label: role === 'ADMIN' ? 'Administrator' : 'Benutzer',
+          }))}
+        />
+        {formError && (
+          <p role="alert" className="rounded-lg bg-red-50 px-3 py-2 text-sm text-red-700">
+            {formError}
+          </p>
+        )}
+        <div className="flex justify-end gap-2 pt-2">
+          <Button type="button" variant="secondary" onClick={onClose}>
+            Abbrechen
+          </Button>
+          <Button type="submit" loading={updateMutation.isPending}>
+            Speichern
+          </Button>
+        </div>
+      </form>
+    </Modal>
+  );
+}
+
+/** Formular: Passwort zurücksetzen. */
+function ResetPasswordModal({ user, onClose }: { user: User; onClose: () => void }): ReactNode {
+  const { showToast } = useToast();
+  const [fieldErrors, setFieldErrors] = useState<Record<string, string>>({});
+  const [formError, setFormError] = useState<string | null>(null);
+
+  const resetMutation = useMutation({
+    mutationFn: (input: { newPassword: string }) => resetUserPassword(user.id, input),
+    onSuccess: () => {
+      showToast('success', `Passwort für "${user.username}" wurde zurückgesetzt`);
+      onClose();
+    },
+    onError: (error) => {
+      if (error instanceof ApiError) {
+        setFormError(error.message);
+        setFieldErrors(fieldErrorsFromApi(error.details));
+      } else {
+        setFormError('Passwort konnte nicht zurückgesetzt werden');
+      }
+    },
+  });
+
+  function handleSubmit(event: FormEvent<HTMLFormElement>): void {
+    event.preventDefault();
+    setFieldErrors({});
+    setFormError(null);
+
+    const formData = new FormData(event.currentTarget);
+    const parsed = resetPasswordSchema.safeParse({
+      newPassword: formData.get('newPassword'),
+    });
+    if (!parsed.success) {
+      setFieldErrors(fieldErrorsFromZod(parsed.error.issues));
+      return;
+    }
+    resetMutation.mutate(parsed.data);
+  }
+
+  return (
+    <Modal
+      open
+      title="Passwort zurücksetzen"
+      description={`Neues Passwort für @${user.username} festlegen. Der Benutzer wird von allen Sitzungen abgemeldet.`}
+      onClose={onClose}
+    >
+      <form onSubmit={handleSubmit} className="space-y-4" noValidate>
+        <Input
+          label="Neues Passwort"
+          name="newPassword"
+          type="password"
+          hint="Mindestens 10 Zeichen"
+          error={fieldErrors.newPassword}
+          autoFocus
+        />
+        {formError && (
+          <p role="alert" className="rounded-lg bg-red-50 px-3 py-2 text-sm text-red-700">
+            {formError}
+          </p>
+        )}
+        <div className="flex justify-end gap-2 pt-2">
+          <Button type="button" variant="secondary" onClick={onClose}>
+            Abbrechen
+          </Button>
+          <Button type="submit" variant="danger" loading={resetMutation.isPending}>
+            Zurücksetzen
+          </Button>
+        </div>
+      </form>
+    </Modal>
+  );
+}
+
+/** Bestätigungsdialog: Benutzer löschen. */
+function DeleteUserModal({ user, onClose }: { user: User; onClose: () => void }): ReactNode {
+  const { showToast } = useToast();
+  const queryClient = useQueryClient();
+  const [formError, setFormError] = useState<string | null>(null);
+
+  const deleteMutation = useMutation({
+    mutationFn: () => deleteUser(user.id),
+    onSuccess: () => {
+      void queryClient.invalidateQueries({ queryKey: ['users'] });
+      showToast('success', `Benutzer "${user.username}" wurde gelöscht`);
+      onClose();
+    },
+    onError: (error) => {
+      setFormError(error instanceof ApiError ? error.message : 'Löschen fehlgeschlagen');
+    },
+  });
+
+  return (
+    <Modal
+      open
+      title="Benutzer löschen"
+      description={`Möchten Sie "${user.displayName}" (@${user.username}) wirklich löschen? Dieser Vorgang kann nicht rückgängig gemacht werden.`}
+      onClose={onClose}
+    >
+      {formError && (
+        <p role="alert" className="mb-4 rounded-lg bg-red-50 px-3 py-2 text-sm text-red-700">
+          {formError}
+        </p>
+      )}
+      <div className="flex justify-end gap-2">
+        <Button variant="secondary" onClick={onClose}>
+          Abbrechen
+        </Button>
+        <Button
+          variant="danger"
+          loading={deleteMutation.isPending}
+          onClick={() => deleteMutation.mutate()}
+        >
+          Endgültig löschen
+        </Button>
+      </div>
+    </Modal>
+  );
+}
+
+/** Benutzerverwaltung (nur Admin): Liste, Anlegen, Bearbeiten, Passwort, Löschen. */
 export function UsersPage(): ReactNode {
+  const { user: currentUser } = useAuth();
+  const queryClient = useQueryClient();
+  const { showToast } = useToast();
+  const [createOpen, setCreateOpen] = useState(false);
+  const [editUser, setEditUser] = useState<User | null>(null);
+  const [resetPasswordUser, setResetPasswordUser] = useState<User | null>(null);
+  const [deleteTarget, setDeleteTarget] = useState<User | null>(null);
+
+  const usersQuery = useQuery({
+    queryKey: ['users'],
+    queryFn: fetchUsers,
+  });
+
+  const toggleActiveMutation = useMutation({
+    mutationFn: (target: User) => updateUser(target.id, { isActive: !target.isActive }),
+    onSuccess: () => {
+      void queryClient.invalidateQueries({ queryKey: ['users'] });
+      showToast('success', 'Status wurde aktualisiert');
+    },
+    onError: (error) => {
+      showToast('error', error instanceof ApiError ? error.message : 'Aktualisierung fehlgeschlagen');
+    },
+  });
+
   return (
     <div className="mx-auto max-w-6xl space-y-6">
-      <div>
-        <h1 className="text-2xl font-bold text-slate-900">Benutzerverwaltung</h1>
-        <p className="mt-1 text-sm text-slate-500">
-          Benutzer anlegen, bearbeiten und verwalten.
-        </p>
+      <div className="flex flex-wrap items-center justify-between gap-3">
+        <div>
+          <h1 className="text-2xl font-bold text-slate-900">Benutzerverwaltung</h1>
+          <p className="mt-1 text-sm text-slate-500">
+            Benutzer anlegen, bearbeiten und verwalten.
+          </p>
+        </div>
+        <Button onClick={() => setCreateOpen(true)}>+ Benutzer anlegen</Button>
       </div>
 
-      <Card>
-        <CardHeader title="Benutzer" description="Alle Benutzer der Plattform" />
-        <CardBody>
-          <EmptyState
-            title="Benutzerverwaltung folgt in Phase 2"
-            description="Die vollständige Benutzerverwaltung (Liste, Anlegen, Bearbeiten, Deaktivieren) wird in Phase 2 implementiert."
-            icon={<span className="text-3xl" aria-hidden="true">👥</span>}
-          />
-        </CardBody>
-      </Card>
+      <div className="overflow-x-auto rounded-xl border border-slate-200 bg-white shadow-sm">
+        <table className="w-full min-w-[720px] text-sm">
+          <thead>
+            <tr className="border-b border-slate-200 bg-slate-50 text-left text-xs uppercase tracking-wide text-slate-500">
+              <th className="px-4 py-3 font-semibold">Benutzer</th>
+              <th className="px-4 py-3 font-semibold">Rolle</th>
+              <th className="px-4 py-3 font-semibold">Status</th>
+              <th className="px-4 py-3 font-semibold">Letzter Login</th>
+              <th className="px-4 py-3 font-semibold">Aktionen</th>
+            </tr>
+          </thead>
+          <tbody>
+            {usersQuery.isLoading && (
+              <tr>
+                <td colSpan={5} className="px-4 py-8 text-center text-slate-500">
+                  Benutzer werden geladen…
+                </td>
+              </tr>
+            )}
+            {usersQuery.isError && (
+              <tr>
+                <td colSpan={5} className="px-4 py-8 text-center text-red-600">
+                  Benutzer konnten nicht geladen werden.
+                </td>
+              </tr>
+            )}
+            {usersQuery.data?.map((user) => (
+              <tr key={user.id} className="border-b border-slate-100 last:border-0">
+                <td className="px-4 py-3">
+                  <div className="font-medium text-slate-900">{user.displayName}</div>
+                  <div className="text-xs text-slate-500">
+                    @{user.username} · {user.email}
+                  </div>
+                </td>
+                <td className="px-4 py-3">
+                  <span
+                    className={`inline-flex rounded-full px-2.5 py-0.5 text-xs font-medium ring-1 ring-inset
+                      ${
+                        user.role === 'ADMIN'
+                          ? 'bg-brand-50 text-brand-700 ring-brand-600/20'
+                          : 'bg-slate-100 text-slate-600 ring-slate-500/20'
+                      }`}
+                  >
+                    {user.role === 'ADMIN' ? 'Administrator' : 'Benutzer'}
+                  </span>
+                </td>
+                <td className="px-4 py-3">
+                  <span
+                    className={`inline-flex rounded-full px-2.5 py-0.5 text-xs font-medium ring-1 ring-inset
+                      ${
+                        user.isActive
+                          ? 'bg-emerald-50 text-emerald-700 ring-emerald-600/20'
+                          : 'bg-red-50 text-red-700 ring-red-600/20'
+                      }`}
+                  >
+                    {user.isActive ? 'Aktiv' : 'Deaktiviert'}
+                  </span>
+                </td>
+                <td className="px-4 py-3 text-slate-500">{formatDate(user.lastLoginAt)}</td>
+                <td className="px-4 py-3">
+                  <div className="flex flex-wrap gap-1">
+                    <Button size="sm" variant="ghost" onClick={() => setEditUser(user)}>
+                      Bearbeiten
+                    </Button>
+                    <Button size="sm" variant="ghost" onClick={() => setResetPasswordUser(user)}>
+                      Passwort
+                    </Button>
+                    {user.id !== currentUser?.id && (
+                      <>
+                        <Button
+                          size="sm"
+                          variant="ghost"
+                          loading={
+                            toggleActiveMutation.isPending &&
+                            toggleActiveMutation.variables?.id === user.id
+                          }
+                          onClick={() => toggleActiveMutation.mutate(user)}
+                        >
+                          {user.isActive ? 'Deaktivieren' : 'Aktivieren'}
+                        </Button>
+                        <Button size="sm" variant="ghost" onClick={() => setDeleteTarget(user)}>
+                          Löschen
+                        </Button>
+                      </>
+                    )}
+                  </div>
+                </td>
+              </tr>
+            ))}
+          </tbody>
+        </table>
+        {usersQuery.data?.length === 0 && (
+          <p className="px-4 py-8 text-center text-slate-500">
+            Noch keine Benutzer vorhanden.
+          </p>
+        )}
+      </div>
+
+      {createOpen && (
+        <CreateUserModal
+          open={createOpen}
+          onClose={() => setCreateOpen(false)}
+          onCreated={() => void queryClient.invalidateQueries({ queryKey: ['users'] })}
+        />
+      )}
+      {editUser && <EditUserModal user={editUser} onClose={() => setEditUser(null)} />}
+      {resetPasswordUser && (
+        <ResetPasswordModal user={resetPasswordUser} onClose={() => setResetPasswordUser(null)} />
+      )}
+      {deleteTarget && (
+        <DeleteUserModal user={deleteTarget} onClose={() => setDeleteTarget(null)} />
+      )}
     </div>
   );
 }

apps/platform-frontend/src/features/profile/profile-page.tsx

@@ -0,0 +1,184 @@
+import { type FormEvent, type ReactNode, useState } from 'react';
+import { useMutation, useQuery } from '@tanstack/react-query';
+import { Button } from '../../components/ui/button';
+import { Card, CardBody, CardHeader } from '../../components/ui/card';
+import { Input } from '../../components/ui/input';
+import { useToast } from '../../components/ui/toast';
+import { ApiError } from '../../lib/api-client';
+import { changePassword, fetchProfile } from '../../lib/users-api';
+import { changePasswordSchema } from '../../lib/schemas';
+
+/** Datumsformat für Profilanzeigen. */
+function formatDate(isoDate: string | null): string {
+  if (!isoDate) {
+    return '–';
+  }
+  return new Date(isoDate).toLocaleDateString('de-DE', {
+    day: '2-digit',
+    month: '2-digit',
+    year: 'numeric',
+    hour: '2-digit',
+    minute: '2-digit',
+  });
+}
+
+/** Profil des angemeldeten Benutzers mit Passwortänderung. */
+export function ProfilePage(): ReactNode {
+  const { showToast } = useToast();
+  const [fieldErrors, setFieldErrors] = useState<Record<string, string>>({});
+  const [formError, setFormError] = useState<string | null>(null);
+
+  const profileQuery = useQuery({
+    queryKey: ['profile'],
+    queryFn: fetchProfile,
+  });
+
+  const changePasswordMutation = useMutation({
+    mutationFn: changePassword,
+    onSuccess: () => {
+      showToast('success', 'Passwort wurde geändert');
+      setFieldErrors({});
+      setFormError(null);
+    },
+    onError: (error) => {
+      if (error instanceof ApiError) {
+        setFormError(error.message);
+        const details = error.details ?? {};
+        const errors: Record<string, string> = {};
+        for (const [key, value] of Object.entries(details)) {
+          errors[key] = Array.isArray(value) ? value[0] : value;
+        }
+        setFieldErrors(errors);
+      } else {
+        setFormError('Passwort konnte nicht geändert werden');
+      }
+    },
+  });
+
+  function handleSubmit(event: FormEvent<HTMLFormElement>): void {
+    event.preventDefault();
+    setFieldErrors({});
+    setFormError(null);
+
+    const formData = new FormData(event.currentTarget);
+    const parsed = changePasswordSchema.safeParse({
+      currentPassword: formData.get('currentPassword'),
+      newPassword: formData.get('newPassword'),
+      confirmPassword: formData.get('confirmPassword'),
+    });
+    if (!parsed.success) {
+      const errors: Record<string, string> = {};
+      for (const issue of parsed.error.issues) {
+        const key = String(issue.path[0] ?? 'form');
+        if (!errors[key]) {
+          errors[key] = issue.message;
+        }
+      }
+      setFieldErrors(errors);
+      return;
+    }
+    changePasswordMutation.mutate(parsed.data);
+  }
+
+  return (
+    <div className="mx-auto max-w-2xl space-y-6">
+      <div>
+        <h1 className="text-2xl font-bold text-slate-900">Mein Profil</h1>
+        <p className="mt-1 text-sm text-slate-500">
+          Ihre persönlichen Daten und Passwort-Einstellungen.
+        </p>
+      </div>
+
+      <Card>
+        <CardHeader title="Persönliche Daten" />
+        <CardBody>
+          {profileQuery.isLoading && <p className="text-sm text-slate-500">Wird geladen…</p>}
+          {profileQuery.isError && (
+            <p className="text-sm text-red-600">Profil konnte nicht geladen werden.</p>
+          )}
+          {profileQuery.data && (
+            <dl className="grid gap-4 sm:grid-cols-2">
+              <div>
+                <dt className="text-xs uppercase tracking-wide text-slate-500">Anzeigename</dt>
+                <dd className="mt-1 text-sm font-medium text-slate-900">
+                  {profileQuery.data.displayName}
+                </dd>
+              </div>
+              <div>
+                <dt className="text-xs uppercase tracking-wide text-slate-500">Benutzername</dt>
+                <dd className="mt-1 text-sm font-medium text-slate-900">
+                  @{profileQuery.data.username}
+                </dd>
+              </div>
+              <div>
+                <dt className="text-xs uppercase tracking-wide text-slate-500">E-Mail</dt>
+                <dd className="mt-1 text-sm font-medium text-slate-900">
+                  {profileQuery.data.email}
+                </dd>
+              </div>
+              <div>
+                <dt className="text-xs uppercase tracking-wide text-slate-500">Rolle</dt>
+                <dd className="mt-1 text-sm font-medium text-slate-900">
+                  {profileQuery.data.role === 'ADMIN' ? 'Administrator' : 'Benutzer'}
+                </dd>
+              </div>
+              <div>
+                <dt className="text-xs uppercase tracking-wide text-slate-500">Letzter Login</dt>
+                <dd className="mt-1 text-sm font-medium text-slate-900">
+                  {formatDate(profileQuery.data.lastLoginAt)}
+                </dd>
+              </div>
+              <div>
+                <dt className="text-xs uppercase tracking-wide text-slate-500">Mitglied seit</dt>
+                <dd className="mt-1 text-sm font-medium text-slate-900">
+                  {formatDate(profileQuery.data.createdAt)}
+                </dd>
+              </div>
+            </dl>
+          )}
+        </CardBody>
+      </Card>
+
+      <Card>
+        <CardHeader
+          title="Passwort ändern"
+          description="Nach der Änderung werden alle anderen Sitzungen abgemeldet."
+        />
+        <CardBody>
+          <form onSubmit={handleSubmit} className="max-w-sm space-y-4" noValidate>
+            <Input
+              label="Aktuelles Passwort"
+              name="currentPassword"
+              type="password"
+              autoComplete="current-password"
+              error={fieldErrors.currentPassword}
+            />
+            <Input
+              label="Neues Passwort"
+              name="newPassword"
+              type="password"
+              autoComplete="new-password"
+              hint="Mindestens 10 Zeichen"
+              error={fieldErrors.newPassword}
+            />
+            <Input
+              label="Neues Passwort bestätigen"
+              name="confirmPassword"
+              type="password"
+              autoComplete="new-password"
+              error={fieldErrors.confirmPassword}
+            />
+            {formError && (
+              <p role="alert" className="rounded-lg bg-red-50 px-3 py-2 text-sm text-red-700">
+                {formError}
+              </p>
+            )}
+            <Button type="submit" loading={changePasswordMutation.isPending}>
+              Passwort ändern
+            </Button>
+          </form>
+        </CardBody>
+      </Card>
+    </div>
+  );
+}

apps/platform-frontend/src/lib/api-client.ts

@@ -10,7 +10,7 @@ export class ApiError extends Error {
   constructor(
     public readonly status: number,
     message: string,
-    public readonly details?: Record<string, string[]>,
+    public readonly details?: Record<string, string | string[]>,
   ) {
     super(message);
     this.name = 'ApiError';

apps/platform-frontend/src/lib/schemas.ts

@@ -35,3 +35,75 @@ export const healthSchema = z.object({
   }),
 });
 export type Health = z.infer<typeof healthSchema>;
+
+/** Benutzer-Datensatz der Admin-API (/api/v1/users). */
+export const userSchema = z.object({
+  id: z.string(),
+  username: z.string(),
+  email: z.string(),
+  displayName: z.string(),
+  role: z.enum(ROLE_NAMES),
+  isActive: z.boolean(),
+  lastLoginAt: z.string().nullable(),
+  createdAt: z.string(),
+});
+export type User = z.infer<typeof userSchema>;
+
+/** Profil des angemeldeten Benutzers (/api/v1/profile). */
+export const profileSchema = z.object({
+  id: z.string(),
+  username: z.string(),
+  email: z.string(),
+  displayName: z.string(),
+  role: z.enum(ROLE_NAMES),
+  lastLoginAt: z.string().nullable(),
+  createdAt: z.string(),
+});
+export type Profile = z.infer<typeof profileSchema>;
+
+/** Benutzer anlegen (Client-Validierung ist UX; Server validiert erneut). */
+export const createUserSchema = z.object({
+  username: z
+    .string()
+    .trim()
+    .min(3, 'Benutzername muss mindestens 3 Zeichen lang sein')
+    .max(100)
+    .regex(/^[A-Za-z0-9._-]+$/, 'Nur Buchstaben, Zahlen sowie . _ - erlaubt'),
+  email: z.string().trim().email('Ungültige E-Mail-Adresse'),
+  displayName: z.string().trim().min(1, 'Anzeigename ist erforderlich'),
+  password: z.string().min(10, 'Passwort muss mindestens 10 Zeichen lang sein'),
+  role: z.enum(ROLE_NAMES),
+});
+export type CreateUserDto = z.infer<typeof createUserSchema>;
+
+/** Benutzer bearbeiten. */
+export const updateUserSchema = z
+  .object({
+    email: z.string().trim().email('Ungültige E-Mail-Adresse').optional(),
+    displayName: z.string().trim().min(1, 'Anzeigename ist erforderlich').optional(),
+    role: z.enum(ROLE_NAMES).optional(),
+    isActive: z.boolean().optional(),
+  })
+  .refine((data) => Object.values(data).some((value) => value !== undefined), {
+    message: 'Mindestens ein Feld ist erforderlich',
+  });
+export type UpdateUserDto = z.infer<typeof updateUserSchema>;
+
+/** Passwort zurücksetzen (Admin). */
+export const resetPasswordSchema = z.object({
+  newPassword: z.string().min(10, 'Passwort muss mindestens 10 Zeichen lang sein'),
+});
+export type ResetPasswordDto = z.infer<typeof resetPasswordSchema>;
+
+/** Eigenes Passwort ändern. */
+export const changePasswordSchema = z
+  .object({
+    currentPassword: z.string().min(1, 'Aktuelles Passwort ist erforderlich'),
+    newPassword: z.string().min(10, 'Passwort muss mindestens 10 Zeichen lang sein'),
+    confirmPassword: z.string().min(1, 'Passwortbestätigung ist erforderlich'),
+  })
+  .refine((data) => data.newPassword === data.confirmPassword, {
+    message: 'Passwörter stimmen nicht überein',
+    path: ['confirmPassword'],
+  });
+export type ChangePasswordDto = z.infer<typeof changePasswordSchema>;

apps/platform-frontend/src/lib/users-api.ts

@@ -0,0 +1,58 @@
+import { apiRequest } from './api-client';
+import {
+  profileSchema,
+  userSchema,
+  type ChangePasswordDto,
+  type CreateUserDto,
+  type Profile,
+  type ResetPasswordDto,
+  type UpdateUserDto,
+  type User,
+} from './schemas';
+
+/** Typsichere API-Funktionen für die Benutzerverwaltung. */
+
+export async function fetchUsers(): Promise<User[]> {
+  const response = await apiRequest<{ users: unknown[] }>('/api/v1/users');
+  return response.users.map((user) => userSchema.parse(user));
+}
+
+export async function createUser(input: CreateUserDto): Promise<User> {
+  const response = await apiRequest<{ user: unknown }>('/api/v1/users', {
+    method: 'POST',
+    body: input,
+  });
+  return userSchema.parse(response.user);
+}
+
+export async function updateUser(id: string, input: UpdateUserDto): Promise<User> {
+  const response = await apiRequest<{ user: unknown }>(`/api/v1/users/${id}`, {
+    method: 'PATCH',
+    body: input,
+  });
+  return userSchema.parse(response.user);
+}
+
+export async function resetUserPassword(id: string, input: ResetPasswordDto): Promise<void> {
+  await apiRequest(`/api/v1/users/${id}/password`, { method: 'PATCH', body: input });
+}
+
+export async function deleteUser(id: string): Promise<void> {
+  await apiRequest(`/api/v1/users/${id}`, { method: 'DELETE' });
+}
+
+export async function fetchProfile(): Promise<Profile> {
+  const response = await apiRequest<{ profile: unknown }>('/api/v1/profile');
+  return profileSchema.parse(response.profile);
+}
+
+export async function changePassword(input: ChangePasswordDto): Promise<void> {
+  // confirmPassword ist nur eine Client-Prüfung und wird nicht gesendet.
+  await apiRequest('/api/v1/profile/password', {
+    method: 'PATCH',
+    body: {
+      currentPassword: input.currentPassword,
+      newPassword: input.newPassword,
+    },
+  });
+}

apps/platform-frontend/src/main.tsx

@@ -4,11 +4,13 @@ import { BrowserRouter, Navigate, Route, Routes } from 'react-router-dom';
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
 import { AppLayout } from './components/layout/app-layout';
 import { RequireAdmin, RequireAuth } from './components/route-guards';
+import { ToastProvider } from './components/ui/toast';
 import { AuthProvider } from './features/auth/auth-context';
 import { LoginPage } from './features/auth/login-page';
 import { DashboardPage } from './features/dashboard/dashboard-page';
 import { SystemStatusPage } from './features/admin/system-status-page';
 import { UsersPage } from './features/admin/users-page';
+import { ProfilePage } from './features/profile/profile-page';
 import { ForbiddenPage, NotFoundPage } from './pages/error-pages';
 import './index.css';
 
@@ -31,6 +33,7 @@ function AppRoutes(): ReactNode {
 
       <Route element={<RequireAuth><AppLayout /></RequireAuth>}>
         <Route path="/" element={<DashboardPage />} />
+        <Route path="/profile" element={<ProfilePage />} />
         <Route
           path="/admin/users"
           element={<RequireAdmin><UsersPage /></RequireAdmin>}
@@ -58,7 +61,9 @@ createRoot(rootElement).render(
     <QueryClientProvider client={queryClient}>
       <BrowserRouter>
         <AuthProvider>
-          <AppRoutes />
+          <ToastProvider>
+            <AppRoutes />
+          </ToastProvider>
         </AuthProvider>
       </BrowserRouter>
     </QueryClientProvider>

docs/ARCHITECTURE.md

@@ -134,8 +134,24 @@ Security Hardening (Penetrationstests, Dependency/Container-Scans, HSTS, Backup/
 | POST | `/api/v1/auth/logout` | Session | Beendet die aktuelle Session |
 | GET | `/api/v1/auth/me` | Session | Angemeldeter Benutzer (Id, Rolle, …) |
 | GET | `/api/v1/health` | Public | Systemstatus (Backend, DB-Latenz, Version, Uptime) |
+| GET | `/api/v1/users` | Admin | Alle Benutzer |
+| POST | `/api/v1/users` | Admin | Benutzer anlegen (409 bei Duplikat) |
+| GET | `/api/v1/users/:id` | Admin | Einzelner Benutzer |
+| PATCH | `/api/v1/users/:id` | Admin | Bearbeiten / Aktivieren / Deaktivieren |
+| PATCH | `/api/v1/users/:id/password` | Admin | Passwort zurücksetzen |
+| DELETE | `/api/v1/users/:id` | Admin | Benutzer löschen |
+| GET | `/api/v1/profile` | Session | Eigenes Profil |
+| PATCH | `/api/v1/profile/password` | Session | Eigenes Passwort ändern |
 
-OpenAPI/Swagger UI: `/api/docs` · Ab Phase 2: `/api/v1/users/*`, `/api/v1/modules/*`, `/api/v1/permissions/*`, `/api/v1/audit/*`.
+OpenAPI/Swagger UI: `/api/docs` · Ab Phase 3: `/api/v1/modules/*`, `/api/v1/permissions/*`, `/api/v1/audit/*`.
+
+### Schutzregeln der Benutzerverwaltung
+
+- Keine Selbst-Deaktivierung und keine Selbst-Löschung (400)
+- Der letzte aktive Administrator kann nicht herabgestuft, deaktiviert oder gelöscht werden (400)
+- Deaktivierte Benutzer werden sofort von allen Sessions abgemeldet
+- Passwort-Reset (Admin) meldet den Benutzer von allen Sessions ab
+- Eigenes Passwort ändern meldet alle übrigen Sessions ab (aktuelle bleibt aktiv)
 
 ## 9. Modul-Vertrag (Ausblick Phase 3+)
 

docs/PHASES.md

@@ -5,7 +5,7 @@ Der Arbeitsplan sieht zehn inkrementelle Phasen vor. Nach jeder Phase muss das S
 | Phase | Bereich | Status |
 |---|---|---|
 | 1 | Grundgerüst (Docker, DB, Login, Rollen) | ✅ Abgeschlossen |
-| 2 | Benutzerverwaltung | ⏳ Geplant |
+| 2 | Benutzerverwaltung | ✅ Abgeschlossen |
 | 3 | Modul-System (Manifest, Installation, Lifecycle) | ⏳ Geplant |
 | 4 | Gateway & dynamisches Routing (`/slug`) | ⏳ Geplant |
 | 5 | Berechtigungssystem (User ↔ Module) | ⏳ Geplant |
@@ -33,9 +33,28 @@ Definition of Done:
 - [x] Admin-Dashboard sichtbar (inkl. Systemstatus)
 - [x] Backend-Unit-Tests (Auth, Session, Passwort, Validierung)
 
-## Nächste Schritte (Phase 2 – Benutzerverwaltung)
+## Phase 2 – Benutzerverwaltung (abgeschlossen)
 
-- Benutzerliste, Benutzer erstellen/bearbeiten/deaktivieren
-- Passwortänderung und Reset durch Admin
-- `GET/POST/PATCH/DELETE /api/v1/users/*` mit `@Roles('ADMIN')`
-- Frontend-Seite `/admin/users` mit Tabelle, Formular und Bestätigungsdialogen
+Definition of Done: Admin kann Benutzer vollständig verwalten.
+
+- [x] `GET/POST/PATCH/DELETE /api/v1/users/*` (nur `@Roles('ADMIN')`)
+- [x] Benutzerliste, Benutzer anlegen (Zod-Validierung, Duplikat-Schutz 409)
+- [x] Benutzer bearbeiten (Anzeigename, E-Mail, Rolle)
+- [x] Benutzer deaktivieren/aktivieren (Sessions werden sofort ungültig)
+- [x] Passwort-Reset durch Admin (alle Sessions des Benutzers werden gelöscht)
+- [x] Schutzregeln: keine Selbst-Deaktivierung/-Löschung, letzter aktiver Admin geschützt
+- [x] Profil-Endpunkte (`GET /api/v1/profile`, `PATCH /api/v1/profile/password`)
+- [x] Eigenes Passwort ändern (Verifikation des aktuellen Passworts, andere Sessions werden abgemeldet)
+- [x] Frontend: Benutzerverwaltungs-Seite (Tabelle, Create/Edit/Reset/Delete-Modals, Toasts)
+- [x] Frontend: Profil-Seite mit Passwortänderung
+- [x] UI-Komponenten: Modal, Select, Toast (Design-System erweitert)
+- [x] Backend-Tests: 49 bestanden (inkl. UsersService, ProfileService)
+- [x] E2E verifiziert: CRUD, RBAC (User → 403), Login-Sperre nach Deaktivierung, Passwort-Flows
+
+## Nächste Schritte (Phase 3 – Modul-System)
+
+- Modul-Datenmodell (`modules`-Tabelle) und Manifest-Vertrag (`module.json`)
+- Modul-Installation als ZIP-Paket (Validierung, Dateien, Registrierung)
+- Modul-Lifecycle (INSTALLED/STARTING/RUNNING/STOPPING/STOPPED/ERROR/DISABLED)
+- Prozessverwaltung der Modul-Prozesse über Supervisor
+- Healthchecks und Statusanzeige im Admin-Bereich