fix(radio): queue navigation, dedup, and similar-first variety (#500) (#503)

* fix(radio): queue navigation, dedup, and similar-first variety (#500)

After a Radio session ran a while, three things broke:

Queue navigation through duplicates. playTrack re-resolved the active
queue index by `findIndex(t.id === track.id)`, returning the *first*
matching id, so reaching the second occurrence of a track snapped
queueIndex back to the earlier slot — highlight jumped and the next
advance played the wrong follow-up. Added an optional
`targetQueueIndex` to playTrack, threaded through next(), previous(),
the audio:ended repeat-one path, queue-row click, and the queue-item
context menu. findIndex stays as the fallback for callers that just
have a track and a fresh queue.

Queue accumulation. enqueueRadio didn't dedupe incoming tracks; the
next() top-up deduped against the live queue but trimmed the played
tail down to HISTORY_KEEP=5, so a song heard 8 ago was gone from
`existingIds` and a later Last.fm/topSongs response could re-add it;
and the `.filter(...)` pass admitted intra-batch repeats (top +
similar overlap is common) because it read the dedup set before
mutating it. A module-level radioSessionSeenIds set, fed by
enqueueRadio and both top-up paths and reset on artist change and
clearQueue, closes all three: trimmed ids stay in the set, ids about
to be replaced (fresh enqueueRadio wiping the pending radio block)
are removed first so callers can re-introduce them, and the dedup
pass mutates the set inline.

Variety. Starting Radio on a track stacked five top tracks of the
seed artist before any similar-artist material played. Switched the
seed path and both top-up paths to lead with similar songs (other
artists) and only fall back to top tracks when similar comes back
empty — preserves the "no Last.fm" graceful degradation but stops
the seed artist from monopolising the front of the queue.

Not affected: gapless audio:track_switched (already index-based, no
findIndex), AudioMuse Instant Mix / Lucky Mix (single-element queues
or enqueue-only paths), the artist-radio path (no seedTrack — already
picks just one top track and fills the rest from similar).

Reported by netherguy4.

* docs: changelog entry for PR #503

Logs the radio queue navigation/dedup/similar-first fix in v1.46.0
"## Fixed".

src/components/ContextMenu.tsx

@@ -1391,19 +1391,20 @@ export default function ContextMenu() {
       }
       // Load radio queue in background — enqueueRadio replaces any pending radio
       // tracks so clicking "Start Radio" again never stacks duplicate batches.
-      // Shuffle so the follow-up tracks feel fresh instead of always being the
-      // same "Top 5" in the same order every time.
+      // Lead with similar songs (other artists) so the listener doesn't get a
+      // wall of the seed artist's own top tracks before anything else plays.
+      // Top tracks stay as a fallback for setups without Last.fm / small
+      // libraries where similar comes back empty (issue #500).
       try {
         const [similar, top] = await Promise.all([getSimilarSongs2(artistId), getTopSongs(artistName)]);
-        // Keep artist top songs and similar-by-artist in two blocks (each shuffled), not one blended pile —
-        // otherwise this feels the same as Instant Mix (track-based similar only).
-        const topTracks = shuffleArray(
-          top.map(songToTrack).filter(t => t.id !== seedTrack.id).map(t => ({ ...t, radioAdded: true as const }))
-        );
         const similarTracks = shuffleArray(
           similar.map(songToTrack).filter(t => t.id !== seedTrack.id).map(t => ({ ...t, radioAdded: true as const }))
         );
-        const radioTracks = [...topTracks, ...similarTracks];
+        const radioTracks = similarTracks.length > 0
+          ? similarTracks
+          : shuffleArray(
+              top.map(songToTrack).filter(t => t.id !== seedTrack.id).map(t => ({ ...t, radioAdded: true as const }))
+            );
         if (radioTracks.length > 0) usePlayerStore.getState().enqueueRadio(radioTracks, artistId);
       } catch (e) {
         console.error('Failed to load radio queue', e);
@@ -2142,7 +2143,7 @@ export default function ContextMenu() {
           const song = item as Track;
           return (
             <>
-              <div className="context-menu-item" onClick={() => handleAction(() => playTrack(song, queue))}>
+              <div className="context-menu-item" onClick={() => handleAction(() => playTrack(song, queue, undefined, undefined, contextMenu.queueIndex))}>
                 <Play size={14} /> {t('contextMenu.playNow')}
               </div>
               <div className="context-menu-item" style={{ color: 'var(--danger)' }} onClick={() => handleAction(() => {

src/components/QueuePanel.tsx

@@ -1063,7 +1063,9 @@ function QueuePanelHostOrSolo() {
                 className={`queue-item ${isPlaying ? 'active' : ''} ${contextMenu.isOpen && contextMenu.type === 'queue-item' && contextMenu.queueIndex === idx ? 'context-active' : ''}`}
                 onClick={() => {
                   suppressNextAutoScrollRef.current = true;
-                  playTrack(track, queue);
+                  // Pass the row index so a click on a duplicate track lands on
+                  // *this* slot, not the first occurrence (issue #500).
+                  playTrack(track, queue, undefined, undefined, idx);
                 }}
                 onContextMenu={(e) => {
                   e.preventDefault();