web: deep-link from RightSidebar to folder/map + anchor-mode timeline + fix root count

RightSidebar:
- Folder + Location rows gain a small ArrowUpRight icon button that
  deep-links into the timeline / map view focused on the photo. OSM
  external link removed; the in-app map nav covers the same job.

Folder navigation:
- New navigateToFolder(path, { focusUid, focusTakenAt }) helper in the
  filters store; LeftSidebar's pickFolder collapses to a one-liner that
  reuses it.
- One-shot pending-focus stash carries both UID and TakenAt across the
  goto. URL-watch effect on the timeline consumes the stash so even
  same-folder navigations (where the filter doesn't change) get
  picked up.

Anchor-mode timeline query:
- listPhotosAround(q, takenAt, after, before) issues two parallel
  PhotoPrism calls (`after:<day-1>` oldest-first + `before:<day+1>`
  newest-first), merges + dedupes newest-first. Uses PhotoPrism's
  existing date-only DSL clauses — no server changes.
- When a deep-link stashes a TakenAt, page 0 of the photosQuery uses
  the merged window so the target photo is loaded even for photos
  buried past the standard newest-first cursor. Pages 1+ are disabled
  in anchor mode (PhotoPrism's day-precision cursor would infinite-loop
  on dense days; users see 120 around the target, refresh to drop the
  anchor).
- After page 0 lands, the existing scrollToIndex(targetIdx) expands the
  windowed render set + scrolls the tile into view.

Map view:
- /map honors `?lat=&lng=&zoom=&focus=` URL params, jumping to the
  photo's coordinates at zoom 17 instead of fitBounds-ing the full
  library. Params are stripped after first apply so a manual zoom-out
  + reload doesn't snap back.

LeftSidebar root count badge:
- Now matches what Cmd+A selects in the timeline. Old code used
  /config.count.all (library aggregate, includes archived/hidden/
  review). Switched to countPhotos('', { merged: true }) which counts
  the actual photo entries the timeline lists.
- countPhotos gains a `merged` option; with merged=true it returns the
  response body length instead of the X-Count header — PhotoPrism's
  X-Count is always the file-row count regardless of merged, so a
  HEIC + JPG companion pair inflated the badge to 2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/src/lib/components/timeline/BulkActionBar.svelte

@@ -54,6 +54,14 @@
 		selection.ids.size > 0 ? selection.ids.size : selection.focused ? 1 : 0
 	);
 	const isBulk = $derived(selection.ids.size > 0);
+	// Filename for the single-focus label. Re-derives whenever
+	// selection.focused flips — cachedPhoto reads from the same query
+	// cache that drives the visible tiles, so the name resolves on the
+	// same tick the tile renders.
+	const focusedPhoto = $derived(selection.focused ? cachedPhoto(selection.focused) : undefined);
+	const focusedName = $derived(
+		focusedPhoto ? photoNameAndDir(focusedPhoto).fileName : ''
+	);
 	// Review section uses a two-button decision flow (Keep / Archive) —
 	// every other action is hidden so the choice can't be confused with
 	// heap-adding / restoring. The S keybinding is rerouted to approve
@@ -248,13 +256,19 @@
 	<div
 		class="flex min-h-9 shrink-0 items-center gap-2 border-t border-border bg-background px-3 py-1"
 	>
-		<span class="shrink-0 text-[11px] font-medium text-foreground">
-			{#if isBulk}
+		{#if isBulk}
+			<span class="shrink-0 text-[11px] font-medium text-foreground">
 				{targetCount} selected
-			{:else}
-				Focused photo
-			{/if}
-		</span>
+			</span>
+		{:else}
+			<span class="shrink-0 text-[11px] font-medium text-muted-foreground">Focused</span>
+			<span
+				class="min-w-0 truncate text-[11px] font-medium text-foreground"
+				title={focusedName || undefined}
+			>
+				{focusedName || 'photo'}
+			</span>
+		{/if}
 
 		<!--
 			`overflow-x-auto` would clip the heap-picker dropdown — CSS