feat(backend): Datenexport-Modul (Modul 21)

ExportModule mit GET /export/colonies.csv, /export/honey-batches.csv,
/export/:entity.json (apiaries/colonies/queens/honey-batches/tasks)
und /export/:report.pdf (honey-batch-traceability via pdfkit).
Ausserdem fehlendes "typecheck"-Skript in package.json ergaenzt
(von CLAUDE.md dokumentiert, war aber nicht vorhanden).

ApiCore-Backend/src/app.module.ts

@@ -20,6 +20,7 @@ import { HoneyBatchesModule } from './honey-batches/honey-batches.module';
 import { StorageModule } from './storage/storage.module';
 import { DashboardModule } from './dashboard/dashboard.module';
 import { SearchModule } from './search/search.module';
+import { ExportModule } from './export/export.module';
 import { JwtAuthGuard } from './auth/guards/jwt-auth.guard';
 import { RolesGuard } from './auth/guards/roles.guard';
 
@@ -45,6 +46,7 @@ import { RolesGuard } from './auth/guards/roles.guard';
     StorageModule,
     DashboardModule,
     SearchModule,
+    ExportModule,
   ],
   controllers: [],
   providers: [