feat: T4 wave 3 - notifications per user, suggestions API, varroa bands, split/queen events

- Schema III: per-user notifications (broadcast fan-out migration,
  category, link, requiredPermissions filter), notification preferences
  and settings endpoints, calendar withdrawal switch, occupiedFrames
- Suggestions API: list/summary with permission visibility and paging,
  accept/dismiss/reopen incl. bulk, SuggestionView on all responses
- Varroa traffic light by season and method, young colonies, treatment
  effect window, sample-based percentage; shared withdrawal-window helper
  on Berlin calendar days; GET /varroa-measurements/thresholds
- ColonySplit and QueenAssigned domain events with calendar and webhook
  handlers
- Outbox claims compare against now() rounded to timestamp(3); fixes the
  flaky e2e claims of rows written with SQL now()

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

ApiCore-Backend/src/common/validation/update-dto-null-handling.spec.ts

@@ -15,6 +15,7 @@ import { UpdateHoneyBatchDto } from '../../honey-batches/dto/update-honey-batch.
 import { UpdateHoneyMeasurementDto } from '../../honey-batches/dto/update-honey-measurement.dto';
 import { UpdateInspectionDto } from '../../inspections/dto/update-inspection.dto';
 import { UpdateLabelTemplateDto } from '../../label-templates/dto/update-label-template.dto';
+import { UpdateNotificationSettingsDto } from '../../notifications/dto/update-notification-settings.dto';
 import { UpdateProductionBatchDto } from '../../production-batches/dto/update-production-batch.dto';
 import { UpdateProductDto } from '../../products/dto/update-product.dto';
 import { UpdateProfileDto } from '../../profile/dto/update-profile.dto';
@@ -78,9 +79,23 @@ const contracts: Record<string, NullContract> = {
       'syncFeeding',
       'syncHarvest',
       'syncQueenAssignment',
+      'syncWithdrawal',
     ],
     clearable: ['groupId'],
   },
+  // quietFrom/quietUntil: null clears them, but only as a pair (the service
+  // judges the merged values).
+  UpdateNotificationSettingsDto: {
+    dto: UpdateNotificationSettingsDto,
+    notNull: [
+      'taskDueEnabled',
+      'digestEnabled',
+      'digestTime',
+      'telegramCategories',
+      'telegramDetail',
+    ],
+    clearable: ['quietFrom', 'quietUntil'],
+  },
   UpdateBottlingBatchDto: {
     dto: UpdateBottlingBatchDto,
     notNull: [