feat(07-04): DkvModule + registry seed + AppModule registration + i18n keys

- dkv.seed.ts: seedDkvModule with slug=dkv-fleet, category=fleet, isSystem=true
- dkv.module.ts: imports ModuleRegistryModule + CalendarModule (CalendarCryptoService)
  provides all 7 DKV services + 2 providers + controller; OnModuleInit seeds registry
- app.module.ts: DkvModule added to imports (ScheduleModule + SettingsModule from Plans 01/03)
- de.json + en.json: complete dkvFleet namespace (50+ keys incl. status, col, form, errors)
- settings namespace extended with categoryGeneral, categorySmtp, smtp sub-object

apps/api/src/app.module.ts

@@ -11,6 +11,7 @@ import { LdapModule } from './ldap/ldap.module';
 import { MailModule } from './mail/mail.module';
 import { CalendarModule } from './calendar/calendar.module';
 import { DashboardModule } from './dashboard/dashboard.module';
+import { DkvModule } from './dkv/dkv.module';
 import { DomaincheckModule } from './domaincheck/domaincheck.module';
 import { ModuleRegistryModule } from './module-registry/module-registry.module';
 import { PrismaModule } from './prisma/prisma.module';
@@ -35,6 +36,7 @@ import { UserModule } from './user/user.module';
     DashboardModule,
     CalendarModule,
     SettingsModule,
+    DkvModule,
   ],
   providers: [
     // Global JWT guard: all routes require auth unless @Public()

apps/api/src/dkv/dkv.module.ts

@@ -0,0 +1,70 @@
+import { Logger, Module, OnModuleInit } from '@nestjs/common';
+import { ModuleRegistryModule } from '../module-registry/module-registry.module';
+import { ModuleRegistryService } from '../module-registry/module-registry.service';
+import { CalendarModule } from '../calendar/calendar.module';
+import { DkvController } from './dkv.controller';
+import { DkvExportService } from './dkv-export.service';
+import { DkvMailService } from './dkv-mail.service';
+import { DkvParserService } from './dkv-parser.service';
+import { DkvSchedulerService } from './dkv-scheduler.service';
+import { DkvService } from './dkv.service';
+import { ExchangeInboxProvider } from './providers/exchange-inbox.provider';
+import { ImapProvider } from './providers/imap.provider';
+import { seedDkvModule } from './dkv.seed';
+
+/**
+ * NestJS module for the DKV Fleet feature.
+ *
+ * Provides the full DKV processing pipeline:
+ * - DkvService: orchestration (poll → parse → export → send → history)
+ * - DkvSchedulerService: dynamic cron job via SchedulerRegistry
+ * - DkvParserService: pdf-parse v2 text extraction + DKV-specific regex
+ * - DkvExportService: xlsx buffer generation + user-files/ management
+ * - DkvMailService: nodemailer.createTransport() at send time
+ * - ImapProvider / ExchangeInboxProvider: inbox access providers
+ *
+ * Imports:
+ * - ModuleRegistryModule: for registry self-seed on init
+ * - CalendarModule: provides CalendarCryptoService (AES-256-GCM encryption)
+ *   re-exported from CalendarModule.exports — no re-declaration needed here.
+ *
+ * PrismaModule is global (no explicit import needed).
+ * ScheduleModule.forRoot() was registered in AppModule by Plan 01.
+ * SettingsModule (for DkvMailService → SettingsService) is imported in AppModule.
+ *
+ * Seeds itself into the module registry on application startup via
+ * OnModuleInit lifecycle hook — same pattern as DomaincheckModule.
+ */
+@Module({
+  imports: [
+    ModuleRegistryModule,
+    CalendarModule, // Provides CalendarCryptoService for inbox credential encryption
+  ],
+  controllers: [DkvController],
+  providers: [
+    DkvService,
+    DkvSchedulerService,
+    DkvParserService,
+    DkvExportService,
+    DkvMailService,
+    ImapProvider,
+    ExchangeInboxProvider,
+  ],
+  exports: [DkvService],
+})
+export class DkvModule implements OnModuleInit {
+  private readonly logger = new Logger(DkvModule.name);
+
+  constructor(
+    private readonly moduleRegistryService: ModuleRegistryService,
+  ) {}
+
+  async onModuleInit(): Promise<void> {
+    try {
+      await seedDkvModule(this.moduleRegistryService);
+      this.logger.log('DKV Fleet module seeded in registry');
+    } catch (error) {
+      this.logger.error('Failed to seed DKV Fleet module', error);
+    }
+  }
+}

apps/api/src/dkv/dkv.seed.ts

@@ -0,0 +1,26 @@
+import { ModuleRegistryService } from '../module-registry/module-registry.service';
+
+/**
+ * Seeds the DKV Fleet module into the module registry.
+ *
+ * Called during DkvModule initialization (OnModuleInit) to ensure
+ * the 'dkv-fleet' module record exists in the database.
+ *
+ * Category 'fleet' identifies this as a fleet-management module.
+ * isSystem: true — not tenant-licensable in v1; available to all tenants.
+ */
+export async function seedDkvModule(
+  moduleRegistryService: ModuleRegistryService,
+): Promise<void> {
+  await moduleRegistryService.seedModule({
+    slug: 'dkv-fleet',
+    name: 'DKV Flotte',
+    version: '1.0.0',
+    category: 'fleet',
+    description: {
+      de: 'DKV-Tankkartenrechnungen automatisch verarbeiten',
+      en: 'Automatically process DKV fuel card invoices',
+    },
+    isSystem: true,
+  });
+}