feat(backend): Webhooks mit HMAC-signierter Auslieferung (Modul 28)

WebhooksModule (WebhookSubscription: URL, Events, Secret, aktiv) mit
Event-Dispatcher, angehaengt an 10 Ereignisse in 8 bestehenden Services
(colony.created, inspection.created, queen.created, queen.replaced,
harvest.created, batch.created, batch.updated, product.stock_changed,
task.created, task.completed). Auslieferung ist best-effort und blockiert
die ausloesende Anfrage nicht bei Fehlern.

ApiCore-Backend/src/inspections/inspections.service.spec.ts

@@ -1,6 +1,7 @@
 import { NotFoundException } from '@nestjs/common';
 import { InspectionsService } from './inspections.service';
 import { PrismaService } from '../prisma/prisma.service';
+import { WebhooksService } from '../webhooks/webhooks.service';
 
 describe('InspectionsService', () => {
   let service: InspectionsService;
@@ -28,7 +29,11 @@ describe('InspectionsService', () => {
       },
       task: { create: jest.fn() },
     };
-    service = new InspectionsService(prisma as unknown as PrismaService);
+    const webhooks = { dispatch: jest.fn().mockResolvedValue(undefined) };
+    service = new InspectionsService(
+      prisma as unknown as PrismaService,
+      webhooks as unknown as WebhooksService,
+    );
   });
 
   it('findById throws NotFoundException when missing', async () => {