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/utils/suggestDateFromPath.ts

@@ -1,8 +1,12 @@
 /**
  * Best-effort calendar date guessed from a photo's filename / parent
- * folders. Returns `YYYY-MM-DD` only when year + month + day are all
- * present and form a real date; returns `null` for year-only or
- * unparseable inputs.
+ * folders. Returns `YYYY-MM-DD`:
+ *   - high-confidence when year + month + day are all parseable
+ *     (basename or path)
+ *   - month-anchored when only year + month appear in the path (day
+ *     synthesised to `01` so the value drops cleanly into a date
+ *     input; the user reviews + adjusts before committing)
+ * Returns `null` for year-only or unparseable inputs.
  *
  * Used by the EXIF Stripped review tab to pre-fill the metadata
  * sidebar's date suggestion row.
@@ -32,8 +36,12 @@ function tryDate(y: number, m: number, d: number): string | null {
 // `20070612` cleanly without bleeding into the trailing timestamp.
 const BASENAME_YMD = /(?<!\d)(\d{4})[-_]?(\d{2})[-_]?(\d{2})(?!\d)/;
 
-// Path variant accepts `/` as a separator too — `2007/06/12`, `2007-06-12/`.
+// Path Y-M-D first (e.g. `2007/06/12`, `2007-06-12/`). Y-M fallback
+// (`2024/01/`, `Photos/2024-01/inner`) trips when the user only foldered
+// by month — the day defaults to `01` so the field has a sensible
+// pre-filled value rather than nothing.
 const PATH_YMD = /(?<!\d)(\d{4})[-_/](\d{2})[-_/](\d{2})(?!\d)/;
+const PATH_YM = /(?<!\d)(\d{4})[-_/](\d{2})(?!\d)/;
 
 export function suggestDateFromPath(input: Input): string | null {
 	const fileName = (input.fileName ?? '').trim();
@@ -46,9 +54,14 @@ export function suggestDateFromPath(input: Input): string | null {
 	}
 
 	if (path) {
-		const pMatch = path.match(PATH_YMD);
-		if (pMatch) {
-			const iso = tryDate(Number(pMatch[1]), Number(pMatch[2]), Number(pMatch[3]));
+		const ymd = path.match(PATH_YMD);
+		if (ymd) {
+			const iso = tryDate(Number(ymd[1]), Number(ymd[2]), Number(ymd[3]));
+			if (iso) return iso;
+		}
+		const ym = path.match(PATH_YM);
+		if (ym) {
+			const iso = tryDate(Number(ym[1]), Number(ym[2]), 1);
 			if (iso) return iso;
 		}
 	}