feat(metadata): wire batch editor over metadata-status buckets (A7)

/metadata/batch?status=pending|failed edits a whole bucket: bulk re-enrich
(AcoustID/MusicBrainz) and stamp common fields onto the selection, with a
select-list and per-track checkboxes. Storage Maintenance failed/missing tabs
link straight into it, closing the A6→A7 flow.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/features/storage/StorageMaintenancePage.tsx

@@ -181,9 +181,20 @@ function TrackListTab({
 
   const from = offset + 1;
   const to = offset + data.items.length;
+  // Broken files map to the `failed` metadata bucket; missing → `pending`.
+  const batchStatus = emptyKey === 'broken' ? 'failed' : 'pending';
 
   return (
     <div style={{ display: 'flex', flexDirection: 'column', gap: '0.25rem' }}>
+      <div style={{ display: 'flex', justifyContent: 'flex-end', marginBottom: '0.5rem' }}>
+        <Button
+          variant="ghost"
+          size="sm"
+          onClick={() => void navigate(`/metadata/batch?status=${batchStatus}`)}
+        >
+          {t('storage.maintenance.editBatch')}
+        </Button>
+      </div>
       {data.items.map((track) => (
         <TrackRow
           key={track.id}