feat: T4 wave 4 - rules suggest, takeover, chains, autopilot A1-A3, suggestions page, varroa bands UI

- Automation rules propose suggestions instead of creating tasks;
  notify per rule config; corrected varroa measurements refresh or
  resolve their suggestion
- Inspection values can be taken over into the colony card
  (occupiedFrames 0-40, strength deprecated); warning counts use the
  same visibility rule as the notification list
- Biotech chains: swarm check after queen cells, queen acceptance
  check, split schedules (raise own, queen cell, queen)
- Season autopilot core with A1 inspection due, A2 varroa measurement,
  A3 recheck after treatment; colony sync and daily step
- Frontend: suggestions page with groups, bulk accept, undo, paging,
  focus management and permission gating
- Frontend: varroa traffic light from seasonal bands, sample size,
  one range request for the colony chart
- Notifications: mark-read answers 404 for rows the user may no
  longer see

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

ApiCore-Frontend/src/lib/dates.ts

@@ -42,3 +42,15 @@ const CALENDAR_DAY_LENGTH = 10;
 export function toCalendarDay(isoTimestamp: string): string {
   return isoTimestamp.slice(0, CALENDAR_DAY_LENGTH);
 }
+
+const BERLIN_DAY = new Intl.DateTimeFormat("en-CA", {
+  timeZone: "Europe/Berlin",
+  year: "numeric",
+  month: "2-digit",
+  day: "2-digit",
+});
+
+/** The Europe/Berlin calendar day of an instant, as "YYYY-MM-DD" (the backend's day). */
+export function berlinCalendarDay(isoTimestamp: string): string {
+  return BERLIN_DAY.format(new Date(isoTimestamp));
+}