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/sidebar/RightSidebar.svelte

@@ -329,11 +329,25 @@
 			{/if}
 		</div>
 
-		<!-- Date suggestion derived from the file/folder path. Shown only
-		     when the photo's stored date is missing or untrusted (the
-		     `stripped_exif` heuristic). Amber styling marks it as
-		     unconfirmed — clicking Apply commits as a manual TakenAt
-		     edit. -->
+		<!-- Taken at -->
+		<div class="flex items-center gap-2">
+			<Calendar class="h-3.5 w-3.5 shrink-0 text-muted-foreground" />
+			<input
+				type="text"
+				inputmode="numeric"
+				placeholder="YYYY-MM-DD"
+				pattern="\d{4}-\d{2}-\d{2}"
+				aria-invalid={!takenAtValid}
+				class="min-w-0 flex-1 rounded border border-transparent bg-transparent px-1 py-0.5 text-xs hover:border-input focus:border-input focus:outline-none focus:ring-1 focus:ring-ring aria-invalid:border-destructive aria-invalid:text-destructive aria-invalid:focus:ring-destructive"
+				bind:value={takenAt}
+				onblur={commitTakenAt}
+			/>
+		</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}
 			<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"
@@ -352,21 +366,6 @@
 			</div>
 		{/if}
 
-		<!-- Taken at -->
-		<div class="flex items-center gap-2">
-			<Calendar class="h-3.5 w-3.5 shrink-0 text-muted-foreground" />
-			<input
-				type="text"
-				inputmode="numeric"
-				placeholder="YYYY-MM-DD"
-				pattern="\d{4}-\d{2}-\d{2}"
-				aria-invalid={!takenAtValid}
-				class="min-w-0 flex-1 rounded border border-transparent bg-transparent px-1 py-0.5 text-xs hover:border-input focus:border-input focus:outline-none focus:ring-1 focus:ring-ring aria-invalid:border-destructive aria-invalid:text-destructive aria-invalid:focus:ring-destructive"
-				bind:value={takenAt}
-				onblur={commitTakenAt}
-			/>
-		</div>
-
 		<!-- Folder (read-only). The `px-1 py-0.5` mirrors the input
 		     padding on filename / date so the read-only text starts at the
 		     same x-offset as the editable rows above — otherwise spans