feat(preview): inline split-pane preview + sidebar metadata pass

Replace the fullscreen PreviewOverlay with an inline top pane above
each grid surface. SplitGrid + InlinePreview render the focused
photo/video inside the host page; a resizableVertical action drives
the divider and the height persists via the view store. Applied to
the timeline, /tags drill-in, /review cause tabs, /photo/[uid], and
/map. selection.focused is now the single source of truth for both
the inline pane and the right sidebar — preview.svelte store and
PreviewOverlay are removed.

Sidebar: drop the thumb; lead with icon-led filename and folder
rows that match the date/place rhythm. Move dims+size to the top
(below date) and camera/lens/exposure into the collapsible File
section. Read-only spans share the input padding so the text column
aligns across rows. Folder row sits between date and dims+size.

VideoPlayer: stop forcing width/height: 100% so videos honour their
intrinsic aspect ratio inside the pane. Key the player on file hash
in InlinePreview so navigating between videos remounts the element
and autoplay fires again.

Sidebar (LeftSidebar): switch the labels badge to a dedicated
countPhotos('label:*') query so it reports photos with a label
rather than PhotoPrism's category roll-up.

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

web/src/routes/+layout.svelte

@@ -4,7 +4,6 @@
 	import { browser } from '$app/environment';
 	import { goto } from '$app/navigation';
 	import { page } from '$app/state';
-	import type { Component } from 'svelte';
 	import { QueryClientProvider } from '@tanstack/svelte-query';
 	import { ModeWatcher } from 'mode-watcher';
 	import { Toaster } from 'svelte-sonner';
@@ -13,7 +12,6 @@
 	import { setLeftSidebarWidth, view } from '$lib/stores/view.svelte';
 	import { resizable } from '$lib/actions/resizable';
 	import { queryClient } from '$lib/queryClient';
-	import { preview } from '$lib/stores/preview.svelte';
 	import { startIndexerWatch, stopIndexerWatch } from '$lib/stores/indexer.svelte';
 	import IndexerStatusPill from '$lib/components/layout/IndexerStatusPill.svelte';
 	import LeftSidebar from '$lib/components/layout/LeftSidebar.svelte';
@@ -56,22 +54,6 @@
 		else stopIndexerWatch();
 	});
 
-	// PreviewOverlay is the full-screen lightbox — keyboard nav, map
-	// pane, exif sidebar. Users who never click into a photo never need
-	// it, so we lazy-import the first time `preview.uid` flips non-null
-	// and keep the loaded module around for the rest of the session
-	// (re-opens skip the network round-trip). Closing the overlay leaves
-	// the component mounted but renders nothing — its internal
-	// `{#if preview.uid !== null}` guard collapses the DOM tree.
-	let PreviewOverlay = $state<Component | null>(null);
-	$effect(() => {
-		if (!browser) return;
-		if (preview.uid !== null && PreviewOverlay === null) {
-			void import('$lib/components/preview/PreviewOverlay.svelte').then((m) => {
-				PreviewOverlay = m.default as Component;
-			});
-		}
-	});
 </script>
 
 <svelte:head>
@@ -129,7 +111,4 @@
 	{:else}
 		{@render children?.()}
 	{/if}
-	{#if PreviewOverlay}
-		<PreviewOverlay />
-	{/if}
 </QueryClientProvider>