feat: three-dot context menu on song rows + search shows songs as rows

- Add ⋮ button to every song-item triggering the context menu (same as right-click)
- Show song-actions always visible on touch devices via @media (hover:none)
- Search results: songs now render as makeSongItem rows instead of cards
  (artists/albums remain as horizontal card rows)
- Fix Android app opening system settings on every launch after notification
  permission denial — now only redirects to settings once using notif_settings_shown flag

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

styles.css

@@ -189,6 +189,7 @@ nav{flex:1;overflow-y:auto;padding:4px 10px}
 .song-dur{font-size:11px;color:var(--text3);font-family:var(--mono)}
 .song-actions{display:flex;gap:2px;opacity:0;transition:opacity .15s}
 .song-item:hover .song-actions{opacity:1}
+@media (hover:none){.song-actions{opacity:1}}
 /* ── PLAYLIST DRAG & DROP ── */
 .song-list.pl-draggable .song-item{grid-template-columns:18px 32px 44px 1fr auto}
 .pl-drag-handle{display:flex;align-items:center;justify-content:center;color:var(--text3);opacity:0;cursor:grab;transition:opacity .15s;touch-action:none}