Client accept/reject votes with keyboard-driven culling

- verdicts table (per link, like ratings), PUT verdict endpoint, typed Verdict enum
- share page: thumbs up/down, verdict filter with counts, view-scoped selection bar
- lightbox: per-page shortcut table (P/X/U, 1-5/0, S), ? help overlay, action
  toast when a keyboard vote auto-advances
- shared useLightbox hook; single keydown subscription reading live state via ref
- album view: per-link thumbs and vote counts; share list shows accept/reject totals
- feedback queries deduped and run concurrently; verdict counts in one scan

frontend/src/components/Thumbs.jsx

@@ -0,0 +1,24 @@
+// Accept/reject vote. `value` is 'accept', 'reject' or null; clicking the
+// active thumb clears it. Without onChange it renders read-only.
+export default function Thumbs({ value, onChange, small }) {
+  const thumb = (verdict, glyph, label) => (
+    <button
+      type="button"
+      className={`thumb${value === verdict ? ' active' : ''}`}
+      disabled={!onChange}
+      onClick={(e) => {
+        e.stopPropagation()
+        onChange(value === verdict ? null : verdict)
+      }}
+      title={onChange ? label : undefined}
+    >
+      {glyph}
+    </button>
+  )
+  return (
+    <span className={`thumbs${small ? ' thumbs-small' : ''}`}>
+      {thumb('accept', '👍', 'Accept (P)')}
+      {thumb('reject', '👎', 'Reject (X)')}
+    </span>
+  )
+}