feat: T4 wave 10 – bottling quality, phenology and honey chain UI, Telegram link/receive and ops

- Bottling quality: water content above the legal limit (strict >) answers
  409 CONFIRMATION_REQUIRED bound to the measured value; prefill for jar
  size, best-before (shelfLifeMonths, month-end clamping) and water content;
  impossible dates give 400; water-content checks in src/common/quality.
- Frontend phenology: "Entwicklung melden" sheet, IndexedDB v4 queue,
  season header on the apiary page, confirmed revoke for all apiaries.
- Frontend honey chain: "Vorschlag aus …" hints with explicit take-over,
  prefill status note, movement ledger with withdraw/correct dialogs.
- Telegram: link tokens (hashed, single use), private-chat receiver with
  lease and offset CAS, bounded poison-update skip, Retry-After, pending
  deliveries skipped on disconnect; system API for deliveries and retry;
  worker-only secret wiring and manifest policy tests.
- ARCHITECTURE.md §7, §9, §10, §11.11–11.13, Annahmen 51–55.

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

ApiCore-Backend/src/common/dates.ts

@@ -55,6 +55,27 @@ export function addDays(day: string, days: number): string {
   return result.toISOString().slice(0, 10);
 }
 
+/**
+ * Calendar months on a YYYY-MM-DD string. A day the target month does not
+ * have is cut to its last day: 2027-01-31 + 1 month is 2027-02-28.
+ */
+export function addMonthsClamped(day: string, months: number): string {
+  const start = dayToDate(day);
+  const monthIndex = start.getUTCMonth() + months;
+  const lastDay = new Date(
+    Date.UTC(start.getUTCFullYear(), monthIndex + 1, 0),
+  ).getUTCDate();
+  return new Date(
+    Date.UTC(
+      start.getUTCFullYear(),
+      monthIndex,
+      Math.min(start.getUTCDate(), lastDay),
+    ),
+  )
+    .toISOString()
+    .slice(0, 10);
+}
+
 /** Whole calendar days from `from` to `to` (negative when `to` is earlier). */
 export function daysBetween(from: string, to: string): number {
   return dayNumber(to) - dayNumber(from);