refactor: tidy playlist-menu label and catch blocks

Pre-push code analysis pass for task #1

ClaudeQueue

frontend/app.js

@@ -1108,8 +1108,7 @@ function openCardMenu(video) {
 
   data.playlists.forEach((pl) => {
     const btn = document.createElement('button');
-    const label = () => ((pl.videos.some((x) => x.id === video.id)) ? '✓ ' : '+ ') + pl.name;
-    btn.textContent = label();
+    btn.textContent = (pl.videos.some((x) => x.id === video.id) ? '✓ ' : '+ ') + pl.name;
     btn.onclick = () => {
       const key = pl.id + ':' + video.id;
       // Guard against rapid double-clicks: the op is keyed by playlist+video,
@@ -1132,7 +1131,7 @@ function openCardMenu(video) {
           }
           persist();
           toast(has ? `Removed from ${pl.name}` : `Added to ${pl.name}`);
-        } catch (e) {
+        } catch {
           toast('⚠ Could not update playlist');
         }
         closeModal();
@@ -1331,7 +1330,7 @@ document.querySelectorAll('.chip').forEach((c) => {
           cachedIds.delete(id);
           markCardCacheState(id, 'none');
           toast('Removed from offline cache');
-        } catch (e) {
+        } catch {
           // Non-blocking error; leave it marked cached and re-enable the button.
           toast('⚠ Could not remove from cache');
         }