Fix progressive cache support in PlaylistSource

The PlaylistSource decoder was hitting EOF prematurely when reading
files that were still being downloaded (progressive cache). Instead
of stopping, it now checks if the download is still ongoing and waits
100ms before retrying.

This preserves the progressive cache behavior: playback can start as
soon as the prebuffer (512KB) is ready, and the decoder will
gracefully wait for more data to be written as the download continues.

Changes:
- Modified decode_and_emit_track() to accept cache and pk parameters
- When EOF is reached (read == 0), check if download is ongoing
- If download is ongoing, wait 100ms and retry instead of stopping
- Only break the loop when download is complete and EOF is reached

Fixes the issue where the decoder would stop prematurely on
partially downloaded files.

pmoaudio-ext/src/sources/playlist_source.rs

@@ -237,11 +237,15 @@ impl NodeLogic for PlaylistSourceLogic {
             tracing::debug!("PlaylistSourceLogic: decoding track: {:?}", file_path);
 
             // Décoder et émettre les chunks PCM
+            // Passer le cache et pk pour gérer le cache progressif
+            let cache_pk = track.cache_pk();
             if let Err(e) = decode_and_emit_track(
                 &file_path,
                 self.chunk_frames,
                 &output,
                 &stop_token,
+                &self.cache,
+                cache_pk,
             )
             .await
             {
@@ -264,11 +268,16 @@ impl NodeLogic for PlaylistSourceLogic {
 // ═══════════════════════════════════════════════════════════════════════════
 
 /// Décode un fichier et émet ses chunks audio
+///
+/// Gère le cache progressif : si EOF est atteint et que le download est toujours en cours,
+/// attend et réessaie au lieu de terminer immédiatement.
 async fn decode_and_emit_track(
     path: &PathBuf,
     chunk_frames: usize,
     output: &[mpsc::Sender<Arc<AudioSegment>>],
     stop_token: &CancellationToken,
+    cache: &Arc<AudioCache>,
+    cache_pk: &str,
 ) -> Result<(), AudioError> {
     // Ouvrir et décoder
     let file = File::open(path)
@@ -320,9 +329,23 @@ async fn decode_and_emit_track(
                     let read = read_result.map_err(|e| {
                         AudioError::IoError(format!("I/O error while decoding: {}", e))
                     })?;
-                    if read == 0 && pending.is_empty() {
-                        break;
+
+                    // Si EOF atteint (read == 0)
+                    if read == 0 {
+                        // Vérifier si le download est toujours en cours (cache progressif)
+                        if cache.get_download(cache_pk).await.is_some() {
+                            // Download en cours - attendre un peu et réessayer
+                            tracing::trace!("decode_and_emit_track: EOF reached but download ongoing, waiting...");
+                            tokio::time::sleep(Duration::from_millis(100)).await;
+                            continue; // Retry la lecture
+                        }
+
+                        // Download terminé - c'est vraiment la fin du fichier
+                        if pending.is_empty() {
+                            break;
+                        }
                     }
+
                     if read > 0 {
                         pending.extend_from_slice(&read_buf[..read]);
                     }