Layer catalog now has 3 actions per layer:
- Sync: downloads from eTerra, stores in PostgreSQL (GisFeature table),
incremental — only new OBJECTIDs fetched, removed ones deleted
- GPKG: direct download from eTerra (existing behavior)
- Local export: generates GPKG from local DB (no eTerra needed)
New features:
- /api/eterra/export-local endpoint — builds GPKG from DB, ZIP for multi-layer
- /api/eterra/sync now uses session-based auth (no credentials in request)
- Category headers show both remote + local feature counts
- Each layer shows local DB count (violet badge) + last sync timestamp
- 'Export local' button in action bar when any layer has local data
- Sync progress message with auto-dismiss
DB schema already had GisFeature + GisSyncRun tables from prior work.