feat(02-03): password reset flow, force-change interceptor, MailModule

- MailModule with SMTP transport configured from ENV variables
- MailService for password reset and welcome emails (plain text, i18n)
- Password reset flow: request-reset (public), reset-password (token-based)
- Change password for logged-in users with current password verification
- Admin reset password endpoint (ADMIN/SUPER_ADMIN only, D-03)
- ForcePasswordChangeInterceptor blocks all routes except change-password,
  logout, me when mustChangePassword=true (D-06, Pitfall 5)
- Frontend: reset-password request page, token reset page, change-password page
- Forgot password link added to login page
- MailHog service added to docker-compose.dev.yml for dev email testing
- SMTP env vars added to docker-compose.yml (defaults to MailHog)
- Complete DE/EN i18n coverage for reset and change password flows
- SUS packages installed: @nestjs-modules/mailer, nodemailer, ldapts

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/api/src/auth/auth.module.ts

@@ -2,6 +2,7 @@ import { Module } from '@nestjs/common';
 import { ConfigService } from '@nestjs/config';
 import { JwtModule } from '@nestjs/jwt';
 import { PassportModule } from '@nestjs/passport';
+import { MailModule } from '../mail/mail.module';
 import { AuthController } from './auth.controller';
 import { AuthService } from './auth.service';
 import { JwtStrategy } from './strategies/jwt.strategy';
@@ -17,6 +18,7 @@ import { LocalStrategy } from './strategies/local.strategy';
       }),
       inject: [ConfigService],
     }),
+    MailModule,
   ],
   controllers: [AuthController],
   providers: [AuthService, LocalStrategy, JwtStrategy],