feat: sync calendar entries to a Microsoft 365 group calendar

Adds a one-way push (ApiCore -> M365) of Aufgaben/Durchsichten/
Behandlungen/Fütterungen/Ernten/Königinnen-Zuordnungen into the calendar
of a Microsoft 365 group, via the Graph API.

- CalendarSyncModule (app-only client-credentials Graph auth, separate
  from the interactive SSO app registration; new env vars
  M365_CALENDAR_TENANT_ID/_CLIENT_ID/_CLIENT_SECRET).
- Outbox + minute-interval cron worker (CalendarSyncOutboxEntry) instead
  of a synchronous push, since Graph calls are too slow/flaky to block a
  domain create request on; failed syncs retry up to 5 times.
- Per-source-type toggle plus a group-ID field, configurable in
  Verwaltung > Automatisierung > Kalender-Sync (Verwaltung > Backup, an
  env var still wins on those fields where one applies to related config).
- Hooked into Tasks/Inspections/Treatments/Feedings/Harvests/Queens at
  their existing create (and Task update/complete) points; entries render
  as all-day Graph events to avoid timezone ambiguity.
- Documents the design decision in ARCHITECTURE.md (Annahme 9), since
  this is a net-new capability the lastenheft doesn't scope.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

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

@@ -4,6 +4,7 @@ import { PrismaService } from '../prisma/prisma.service';
 import { WebhooksService } from '../webhooks/webhooks.service';
 import { AutomationService } from '../automation/automation.service';
 import { AuditLogService } from '../audit/audit-log.service';
+import { CalendarSyncService } from '../calendar-sync/calendar-sync.service';
 
 describe('InspectionsService', () => {
   let service: InspectionsService;
@@ -39,11 +40,13 @@ describe('InspectionsService', () => {
       evaluateInspection: jest.fn().mockResolvedValue(undefined),
     };
     auditLog = { record: jest.fn().mockResolvedValue(undefined) };
+    const calendarSync = { enqueue: jest.fn(), cancel: jest.fn() };
     service = new InspectionsService(
       prisma as unknown as PrismaService,
       webhooks as unknown as WebhooksService,
       automation as unknown as AutomationService,
       auditLog as unknown as AuditLogService,
+      calendarSync as unknown as CalendarSyncService,
     );
   });