feat: refactor grouping views into card-grid browse pattern

Replace Timeline-based grouped views (tags, colors, rated) with
dedicated card-grid components that drill into Timeline detail views
on click/Enter. Adds shared useCardGridNav hook for arrow-key
navigation across all four card grids (tags, colors, rated, people).

- TagsView, ColorsView, RatedView: card grid → inline Timeline detail
- PeopleView: migrated to same pattern (Timeline replaces custom grid)
- Tags endpoint: fall back to first associated photo for representative
- Filter store: add ratingMax for exact rating filtering in RatedView
- Timeline: remove tag/rating/color grouping; skip date headers when
  groupBy != 'date' so detail views render flat grids
- SettingsDialog: bump z-index above Leaflet map layers

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

frontend/src/hooks/usePhotosQuery.ts

@@ -32,6 +32,7 @@ export function usePhotosQuery() {
   const dateTo = useFilterStore((s) => s.dateTo)
   const mediaTypes = useFilterStore((s) => s.mediaTypes)
   const ratingMin = useFilterStore((s) => s.ratingMin)
+  const ratingMax = useFilterStore((s) => s.ratingMax)
   const colorLabel = useFilterStore((s) => s.colorLabel)
   const flag = useFilterStore((s) => s.flag)
   const heapId = useFilterStore((s) => s.heapId)
@@ -50,6 +51,7 @@ export function usePhotosQuery() {
         dateTo,
         mediaTypes,
         ratingMin,
+        ratingMax,
         colorLabel,
         flag,
         heapId,
@@ -60,7 +62,7 @@ export function usePhotosQuery() {
         sortBy,
         sortOrder,
       }),
-    [q, dateFrom, dateTo, mediaTypes, ratingMin, colorLabel, flag, heapId, folderId, tagIds, duplicates, groupBy, sortBy, sortOrder]
+    [q, dateFrom, dateTo, mediaTypes, ratingMin, ratingMax, colorLabel, flag, heapId, folderId, tagIds, duplicates, groupBy, sortBy, sortOrder]
   )
 
   const queryClient = useQueryClient()