web(review): YYYY/MM path fallback + suggestion row below date + tighten 'a' gate

- suggestDateFromPath: when only year+month appear in the path
  (e.g. 2024/01/), synthesize day=01 so date-only foldering yields
  a usable suggestion instead of null.
- RightSidebar: move the suggestion row below the Taken-at input.
- BulkActionBar + gridKeyNav: show the "Accept date & Keep" button
  and fire the bare 'a' shortcut only when EVERY targeted photo has
  a path-derivable date — no more silent approve-without-fix for
  mixed selections.
- gridKeyNav: drop local cachedPhoto duplicate, use the shared one.

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

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

@@ -65,7 +65,12 @@
 	const onExifStrippedTab = $derived(
 		isReview && page.url.searchParams.get('tab') === 'stripped_exif'
 	);
-	const hasAnySuggestion = $derived.by(() => {
+	// Surface the button only when EVERY targeted photo has a derivable
+	// suggestion — otherwise clicking it would silently approve some
+	// photos without a date fix, which contradicts the verb. A uid not in
+	// any cache also counts as "no suggestion" so we don't promise
+	// something we can't verify.
+	const allHaveSuggestion = $derived.by(() => {
 		if (!onExifStrippedTab) return false;
 		const ids =
 			selection.ids.size > 0
@@ -73,13 +78,13 @@
 				: selection.focused
 					? [selection.focused]
 					: [];
+		if (ids.length === 0) return false;
 		for (const id of ids) {
 			const p = cachedPhoto(id);
-			if (p && suggestDateFromPath({ fileName: p.FileName, path: p.Path })) {
-				return true;
-			}
+			if (!p) return false;
+			if (!suggestDateFromPath({ fileName: p.FileName, path: p.Path })) return false;
 		}
-		return false;
+		return true;
 	});
 	// Archive section is the parallel two-button flow: Keep (restore back
 	// to the timeline) or Delete (permanent, no undo). X is repurposed
@@ -271,12 +276,11 @@
 					✓ Keep
 					<kbd class="rounded bg-muted px-1 text-[9px] font-medium text-muted-foreground">S</kbd>
 				</button>
-				{#if hasAnySuggestion}
-					<!-- Surfaces only when at least one selected photo has a
-					     derivable date from its path AND lacks a trusted
-					     TakenAt. Applies the suggested date patch then
-					     approves in one go; uids without a usable suggestion
-					     are just approved. -->
+				{#if allHaveSuggestion}
+					<!-- Visible only when every selected photo has a path-
+					     derivable date. Clicking applies each photo's
+					     suggestion then approves it; mirrored by the bare
+					     `a` shortcut in gridKeyNav. -->
 					<button
 						class="inline-flex items-center gap-1 rounded border border-amber-400/60 bg-amber-100/40 px-2 py-0.5 text-[11px] text-amber-800 hover:bg-amber-100 disabled:opacity-50 dark:border-amber-400/40 dark:bg-amber-500/15 dark:text-amber-200 dark:hover:bg-amber-500/25"
 						disabled={busy}