web(review): confidence-aware date guesser with combined filename + path signals

Refactor suggestDateFromPath to combine multiple signals instead of
trying patterns in priority order:

- Filename Y-M-D corroborated by path Y-M/Y-M-D → HIGH (filename-
  agrees-path). Fixes the case where a Samsung-style 20240226_xxx.jpg
  under 2024/02/ was returning the path-only 2024-02-01.
- Filename Y-M-D with no path signal → HIGH (filename-only).
- 10/13-digit Unix epoch in basename → HIGH (unix-timestamp) —
  covers WeChat (mmexport...) and FB saves.
- Path Y-M-D → HIGH (path-ymd).
- Path Y-M only → MEDIUM (path-ym-default-day, synthesised day=01).
  Sidebar row labels these "(estimated day)" so the user knows.

Filename parser now accepts `.` and space separators (covers macOS
screenshots, manual 2024.02.26 renames). Path parser accepts `.` too.
OriginalName participates as a secondary filename signal when present
and different from the on-disk basename.

Patterns we explicitly DO NOT parse, to avoid silent date flips:
DD-MM-YYYY / MM-DD-YYYY, 2-digit years, bare camera sequence numbers.

Add photoNameAndDir(p) helper next to primaryFile so RightSidebar,
BulkActionBar, photoActions, and gridKeyNav all derive {fileName,
path} the same way — fixes the bug where photo.FileName was
undefined on the single-photo detail endpoint and the basename branch
was being skipped entirely.

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

web/src/lib/components/sidebar/RightSidebar.svelte

@@ -38,7 +38,7 @@
 	import { isAuthenticated } from '$lib/stores/session.svelte';
 	import { push as pushUndo } from '$lib/stores/undo.svelte';
 	import { getMetadataSectionOpen, setMetadataSection } from '$lib/stores/view.svelte';
-	import { primaryFile, type PpPhoto } from '$lib/types/photoprism';
+	import { photoNameAndDir, primaryFile, type PpPhoto } from '$lib/types/photoprism';
 	import { COLOR_SWATCHES } from '$lib/utils/tagGroups';
 	import { suggestDateFromPath } from '$lib/utils/suggestDateFromPath';
 
@@ -139,15 +139,20 @@
 		page.url.pathname === '/review' &&
 			page.url.searchParams.get('tab') === 'stripped_exif'
 	);
-	const dateSuggestion = $derived(
-		suggestDateFromPath({ fileName: photo.FileName, path: photo.Path })
-	);
+	const dateSuggestion = $derived.by(() => {
+		const { fileName, path } = photoNameAndDir(photo);
+		return suggestDateFromPath({
+			fileName,
+			originalName: photo.OriginalName,
+			path
+		});
+	});
 	const showDateSuggestion = $derived(
-		onExifStrippedTab && !!dateSuggestion && dateSuggestion !== takenAt
+		onExifStrippedTab && !!dateSuggestion && dateSuggestion.iso !== takenAt
 	);
 	function applyDateSuggestion() {
 		if (!dateSuggestion) return;
-		takenAt = dateSuggestion;
+		takenAt = dateSuggestion.iso;
 		commitTakenAt();
 	}
 	function commitTakenAt() {
@@ -344,17 +349,23 @@
 			/>
 		</div>
 
-		<!-- Date suggestion derived from the file/folder path. Only shown
-		     on the EXIF Stripped review tab; amber styling marks it as
-		     unconfirmed. Apply writes the value into the date input above
-		     and commits as a manual TakenAt edit. -->
-		{#if showDateSuggestion}
+		<!-- Date suggestion derived from filename / folder signals. Only
+		     shown on the EXIF Stripped review tab; amber styling marks
+		     it as unconfirmed. `(estimated day)` hint appears when the
+		     day was synthesised because only Y-M was available — same
+		     row, just so the user knows that part is fabricated. Apply
+		     writes the value into the date input above and commits as
+		     a manual TakenAt edit. -->
+		{#if showDateSuggestion && dateSuggestion}
 			<div
 				class="flex items-center gap-2 rounded border border-amber-300/70 bg-amber-50/40 px-1.5 py-1 text-[11px] text-amber-700 dark:border-amber-500/40 dark:bg-amber-500/10 dark:text-amber-300"
 			>
 				<Folder class="h-3.5 w-3.5 shrink-0" />
 				<span class="min-w-0 flex-1 truncate">
-					Suggested from path: <span class="font-medium">{dateSuggestion}</span>
+					Suggested from path: <span class="font-medium">{dateSuggestion.iso}</span>
+					{#if dateSuggestion.source === 'path-ym-default-day'}
+						<span class="text-amber-600/80 dark:text-amber-400/70">(estimated day)</span>
+					{/if}
 				</span>
 				<button
 					type="button"