feat: platform backbone and field capture, first part (checkpoint)

Platform backbone (plan 2026-10-13-plattform-rueckgrat), reviewed tasks:
- run roles api/worker/job/all with shared startup checks (Task 1)
- schema and migration for DomainEvent, deliveries, JobRun, ThrottlerHit (Task 2)
- audit, notifications and domain events written in the same transaction (Task 3)
- dispatcher with SKIP LOCKED claims, retries and stale release (Task 4)
- worker building blocks: tick, LISTEN/NOTIFY wake-up, health (Task 5)
- worker process and entry points (Task 6)
- throttler counters in Postgres (Task 19)
- separate keys per purpose with key ring (Task 20)
- public origin page without exact location (Task 22)
- shop keys split into read and write (Task 23)
- Kustomize base, components, overlay encry, CI validation (Task 26)

Field capture T3 (plan 2026-10-13-t3-erfassung-am-stand), reviewed tasks:
- brood frames, read endpoints, apiary overview and offline pack
- network basics, offline queue v3, navigation sheets, form building blocks
- new inspection with last-time hints and weather, varroa per day,
  treatment prefill, apiary page with round
- inspection photo (Task 10) is implemented, review pending

Not rolled out. Remaining tasks follow in later commits.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

ApiCore-Backend/src/documents/documents.controller.ts

@@ -24,6 +24,7 @@ import { isAllowedDocumentMimeType } from './document-mime-types';
 import { CreateDocumentDto } from './dto/create-document.dto';
 import { UpdateDocumentDto } from './dto/update-document.dto';
 import { DocumentsService } from './documents.service';
+import { Idempotent } from '../common/idempotency/idempotent.decorator';
 
 const MAX_FILE_SIZE_BYTES = 10 * 1024 * 1024;
 
@@ -60,6 +61,7 @@ export class DocumentsController {
   }
 
   @RequirePermission('documents:upload')
+  @Idempotent()
   @Post()
   @ApiConsumes('multipart/form-data')
   @UseInterceptors(