feat(parcel-sync): incremental sync, smart export, auto-refresh + weekend deep sync

Sync Incremental:
- Add fetchObjectIds (returnIdsOnly) to eterra-client — fetches only OBJECTIDs in 1 request
- Add fetchFeaturesByObjectIds — downloads only delta features by OBJECTID IN (...)
- Rewrite syncLayer: compare remote IDs vs local, download only new features
- Fallback to full sync for first sync, forceFullSync, or delta > 50%
- Reduces sync time from ~10 min to ~5-10s for typical updates

Smart Export Tab:
- Hero buttons detect DB freshness — use export-local (instant) when data is fresh
- Dynamic subtitles: "Din DB (sync acum Xh)" / "Sync incremental" / "Sync complet"
- Re-sync link when data is fresh but user wants forced refresh
- Removed duplicate "Descarca din DB" buttons from background section

Auto-Refresh Scheduler:
- Self-contained timer via instrumentation.ts (Next.js startup hook)
- Weekday 1-5 AM: incremental refresh for existing UATs in DB
- Staggered processing with random delays between UATs
- Health check before processing, respects eTerra maintenance

Weekend Deep Sync:
- Full Magic processing for 9 large municipalities (Cluj, Bistrita, TgMures, etc.)
- Runs Fri/Sat/Sun 23:00-04:00, round-robin intercalated between cities
- 4 steps per city: sync terenuri, sync cladiri, import no-geom, enrichment
- State persisted in KeyValueStore — survives restarts, continues across nights
- Email status report at end of each session via Brevo SMTP
- Admin page at /wds: add/remove cities, view progress, reset
- Hint link on export tab pointing to /wds

API endpoints:
- POST /api/eterra/auto-refresh — N8N-compatible cron endpoint (Bearer token auth)
- GET/POST /api/eterra/weekend-sync — queue management for /wds page

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -68,6 +68,8 @@ services:
       - NOTIFICATION_FROM_EMAIL=noreply@beletage.ro
       - NOTIFICATION_FROM_NAME=Alerte Termene
       - NOTIFICATION_CRON_SECRET=1547a198feca43af6c05622588c6d3b820bad5163b8c20175b2b5bbf8fc1a987
+      # Weekend Deep Sync email reports (comma-separated for multiple recipients)
+      - WEEKEND_SYNC_EMAIL=${WEEKEND_SYNC_EMAIL:-}
       # Portal-only users (comma-separated, redirected to /portal)
       - PORTAL_ONLY_USERS=dtiurbe,d.tiurbe
       # Address Book API (inter-service auth for external tools)