feat: add tag filter for assets

[Majorfi]

Closes #51 — lets you filter photos by an Immich tag across the grid and map, so already-tagged images can be found and mass-geolocated.

Backend

• New tags / assetTags tables (migration 016), synced from Immich via getTags + getTagAssetIDs with a syncTags routine mirroring syncAlbums.
• tagID threaded through asset, map-marker, day-count and page-info queries; new GET /tags endpoint for the dropdown.
• Map-marker queries now also honor startDate/endDate.
• getTags count joins through to real assets, excluding orphaned rows and stack-secondary / hidden-library assets, so the badge matches the filtered list.
• Tag and album sync now advance updatedAt only after assets are replaced — a transient fetch failure is retried next sync instead of leaving membership stale; per-item failures are isolated.
• deleteUserSyncData clears tags/assetTags on API-key change.

Frontend

• TagFilterGroup searchable dropdown, disabled on the album list and cleared when leaving an album.
• tagID persisted in the URL and threaded through view/catalog/map state.
• Map viewport re-fits when the tag or date filter changes the marker set.
• URL sync reads a live ref so chained filter changes no longer clobber one another.

Tests

• New backend regression tests for the tag-count fix, deferred-updatedAt sync (tag and album), and the failed-fetch-recovers behavior.
• Full backend suite + go vet pass; frontend tsc + eslint clean.
• Tag/date map re-fit verified manually in the running app.

[Copilot]

Pull request overview

Adds an Immich tag-based filter that propagates end-to-end (URL/state → frontend grid/map → backend queries), enabling workflows like finding already-tagged photos and mass geolocating them.

Changes:

• Introduces tag persistence and selection in frontend state/URL, plus a searchable TagFilterGroup UI control.
• Adds backend tag storage + sync from Immich and exposes tags via a new GET /tags endpoint.
• Threads tagID (and for map markers, date range) through asset, day-count, page-info, and map-marker queries.

Reviewed changes

Copilot reviewed 42 out of 42 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/utils/view.ts	Adds URL param constant for tag selection.
src/shared/types/tag.ts	Introduces shared tag row type for frontend consumption.
src/shared/types/context.ts	Extends view/map context types to include tag selection and dates.
src/shared/services/backendApi.ts	Threads tagID into asset/day-count/page-info/map-marker requests; adds fetchTags().
src/shared/services/backendApi.guards.ts	Adds runtime guard for tag payloads.
src/shared/context/useViewDomain.ts	Wires tag selection into view domain + URL sync; clears tag in album list mode.
src/shared/context/useUIMapController.ts	Passes tag selection through map controller inputs.
src/shared/context/useProviderValues.ts	Propagates tag selection + dates through provider memoization.
src/shared/context/useCatalogDomain.ts	Threads tag selection into asset loading hook.
src/shared/context/useAppProviderState.ts	Integrates tag state into app provider wiring.
src/shared/components/PhotoListContainer.tsx	Clears tag when switching into album mode; passes tag props to filter bar.
src/shared/components/PhotoList.tsx	Adds tag props to filter bar composition and disables tag filter on album list.
src/features/tags/useTags.ts	New hook to fetch tags lazily (on-demand) with abort handling.
src/features/photoGrid/useAssets.ts	Adds tag dependency to asset loading and refresh logic.
src/features/map/hooks/useMapViewModel.ts	Threads tag/date into map marker loading and view model output.
src/features/map/hooks/useMapViewController.ts	Includes tag/date in controller dependencies for fit/reload behavior.
src/features/map/hooks/useMapViewAutoFit.ts	Resets auto-fit when tag/date filters change (defer fit until markers update).
src/features/map/hooks/useMapMarkers.ts	Threads tag/date into map marker fetch and reload triggers.
src/features/map/hooks/useFocusMapAsset.ts	Passes selected tag into focus resolution flow.
src/features/map/hooks/useFocusMapAsset.flow.ts	Threads tag into page-info queries when resolving focus target.
src/features/filterBar/useURLState.ts	Persists tag in URL state and switches URL sync to a live ref model.
src/features/filterBar/useDayCounts.ts	Threads tag filter into day-count fetching.
src/features/filterBar/TagFilterGroup.tsx	New searchable tag dropdown UI component.
src/features/filterBar/FilterBar.tsx	Renders tag filter group and wires props.
src/features/albums/useAlbums.ts	Adjusts album reload behavior when date/gps filters change.
backend/types.go	Adds backend tag row + Immich tag response types.
backend/syncTags.go	Implements tag metadata upsert + asset membership sync.
backend/syncService.go	Integrates tag sync; changes album sync stamping behavior; adds tag fetch limit.
backend/syncService_test.go	Adds regression tests for deferred updatedAt stamping and recovery behavior.
backend/migrations/016_add_tags.sql	Adds tags and assetTags tables and index.
backend/migrations_test.go	Updates expected migration version to 16.
backend/main.go	Registers protected GET /tags route.
backend/interfaces.go	Extends store interfaces to support tags and tag-aware queries.
backend/immichClient.go	Adds Immich tag list + tag asset search calls.
backend/handlersAuth.go	Updates map marker count calls for new signature.
backend/handlers.go	Threads tag/date into handlers; adds handleGetTags; validates map marker date params.
backend/handlers_test.go	Updates existing tests for new filtered-assets signature.
backend/databaseTags.go	Adds tag persistence, tag membership replacement, and tag list query w/ counts.
backend/databaseLibraries_test.go	Updates map marker/asset query calls for new signatures.
backend/databaseAlbums.go	Adds setAlbumSynced() helper to stamp updatedAt post-success.
backend/database.go	Adds tag-aware asset filters, tag/date-aware marker filters, and tag-aware page-info logic.
backend/database_test.go	Updates tests and adds coverage for tag-filtered queries and tag counts.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[muxmix]

Thank you, very useful, I was able to geolocalize hundreds of images in a few minutes