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/automation/varroa-threshold.ts

@@ -0,0 +1,30 @@
+import type { AutomationRule } from '../../generated/prisma';
+
+/** Default natural mite fall (mites per day) that triggers the varroa rule. */
+export const DEFAULT_VARROA_THRESHOLD_MITES_PER_DAY = 10;
+
+/**
+ * Effective varroa threshold of the VARROA_THRESHOLD rule.
+ * - no rule row yet: the default rule applies (ensureDefaults creates it active)
+ * - inactive rule: null (no threshold in force)
+ * - active rule: the configured value, or the default if it is not a
+ *   positive finite number (a hand-edited config must never disable the check).
+ */
+export function varroaThresholdOf(
+  rule: Pick<AutomationRule, 'active' | 'config'> | null,
+): number | null {
+  if (rule === null) {
+    return DEFAULT_VARROA_THRESHOLD_MITES_PER_DAY;
+  }
+  if (!rule.active) {
+    return null;
+  }
+  const config = rule.config;
+  if (typeof config !== 'object' || config === null || Array.isArray(config)) {
+    return DEFAULT_VARROA_THRESHOLD_MITES_PER_DAY;
+  }
+  const value = (config as Record<string, unknown>).thresholdMitesPerDay;
+  return typeof value === 'number' && Number.isFinite(value) && value > 0
+    ? value
+    : DEFAULT_VARROA_THRESHOLD_MITES_PER_DAY;
+}