feat: RBAC Phase 3 - LegacyRole-Enum, RolesGuard und @Roles vollstaendig entfernt

Letzte Phase des RBAC-Umbaus: die transitionale Rollen-Infrastruktur,
die seit Phase 1 parallel zum neuen Role/Permission-System mitlief,
ist jetzt komplett weg.

- Prisma-Migration: User.legacyRole-Spalte und LegacyRole-Enum
  gedroppt (nichts liest die Spalte mehr, seit Phase 2 jeder Controller
  auf @RequirePermission laeuft).
- roles.guard.ts, roles.guard.spec.ts, roles.decorator.ts geloescht;
  RolesGuard aus den APP_GUARD-Providern entfernt.
- AuthenticatedUser/JWT-Payload verlieren das role-Feld (permissions
  werden ohnehin frisch pro Request aus der DB aufgeloest, nicht aus
  dem Claim).
- Users-API: CreateUserDto/UpdateUserDto akzeptieren jetzt roleId
  (eine echte Role.id) statt der alten role-Enum-Werte; UsersService
  validiert, dass die Rolle existiert und aktiv ist, bevor sie
  zugewiesen wird.
- Alle 34 e2e-Fixtures und der Seed-Script folgen dem neuen Schema.

Verifiziert: tsc, lint, build, unit (220/220), volle e2e-Suite
159/159 gruen - keine uebersprungenen Tests.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

ApiCore-Backend/src/auth/guards/roles.guard.spec.ts

@@ -1,48 +0,0 @@
-import { ExecutionContext } from '@nestjs/common';
-import { Reflector } from '@nestjs/core';
-import { RolesGuard } from './roles.guard';
-import { LegacyRole as Role } from '../../../generated/prisma';
-
-function createContext(user: { role: Role } | undefined): ExecutionContext {
-  return {
-    getHandler: () => ({}),
-    getClass: () => ({}),
-    switchToHttp: () => ({
-      getRequest: () => ({ user }),
-    }),
-  } as unknown as ExecutionContext;
-}
-
-describe('RolesGuard', () => {
-  it('allows access when no roles are required', () => {
-    const reflector = {
-      getAllAndOverride: () => undefined,
-    } as unknown as Reflector;
-    const guard = new RolesGuard(reflector);
-    expect(guard.canActivate(createContext(undefined))).toBe(true);
-  });
-
-  it('denies access when the user role does not match', () => {
-    const reflector = {
-      getAllAndOverride: () => [Role.ADMIN],
-    } as unknown as Reflector;
-    const guard = new RolesGuard(reflector);
-    expect(guard.canActivate(createContext({ role: Role.STAFF }))).toBe(false);
-  });
-
-  it('allows access when the user role matches', () => {
-    const reflector = {
-      getAllAndOverride: () => [Role.ADMIN],
-    } as unknown as Reflector;
-    const guard = new RolesGuard(reflector);
-    expect(guard.canActivate(createContext({ role: Role.ADMIN }))).toBe(true);
-  });
-
-  it('denies access when no user is attached to the request', () => {
-    const reflector = {
-      getAllAndOverride: () => [Role.ADMIN],
-    } as unknown as Reflector;
-    const guard = new RolesGuard(reflector);
-    expect(guard.canActivate(createContext(undefined))).toBe(false);
-  });
-});

ApiCore-Backend/src/auth/guards/roles.guard.ts

@@ -1,27 +0,0 @@
-import { CanActivate, ExecutionContext, Injectable } from '@nestjs/common';
-import { Reflector } from '@nestjs/core';
-import { LegacyRole as Role } from '../../../generated/prisma';
-import { ROLES_KEY } from '../decorators/roles.decorator';
-import { AuthenticatedUser } from '../types/authenticated-user';
-
-interface RequestWithUser {
-  user?: AuthenticatedUser;
-}
-
-@Injectable()
-export class RolesGuard implements CanActivate {
-  constructor(private readonly reflector: Reflector) {}
-
-  canActivate(context: ExecutionContext): boolean {
-    const requiredRoles = this.reflector.getAllAndOverride<Role[]>(ROLES_KEY, [
-      context.getHandler(),
-      context.getClass(),
-    ]);
-    if (!requiredRoles || requiredRoles.length === 0) {
-      return true;
-    }
-    const request = context.switchToHttp().getRequest<RequestWithUser>();
-    const user = request.user;
-    return !!user && requiredRoles.includes(user.role);
-  }
-}