Restore IsStreamingMode on recovery; guard superseded-load else-branch

RecoverFromFailedRefill now sets IsStreamingMode=true so the in-place
seek-retry route isn't wedged. The generic-catch unload path is gated on
the loadCts identity, so a superseded load no longer clobbers a newer
operation's state.

DeepDrftPublic.Client/Services/StreamingAudioPlayerService.cs

@@ -295,15 +295,22 @@ public class StreamingAudioPlayerService : AudioPlayerService, IStreamingPlayerS
             {
                 await RecoverFromFailedRefill(CurrentTime, userError);
             }
-            else
+            else if (ReferenceEquals(_streamingCancellation, loadCts))
             {
-                // First-segment failure (nothing buffered / playing yet) or superseded load: the
-                // normal unload-to-error path is correct — no buffered tail to halt.
+                // First-segment failure (nothing buffered / playing yet), still the active operation:
+                // the normal unload-to-error path is correct — nothing is in the scheduler to halt.
                 ErrorMessage = userError;
                 LoadProgress = 0;
                 IsLoaded = false;
                 IsStreamingMode = false;
             }
+            else
+            {
+                // Superseded load: a newer seek (or track switch) has already claimed _streamingCancellation
+                // and owns all shared state. Writing IsLoaded/IsStreamingMode here would corrupt the live
+                // operation — mirror the OCE catch's identity guard and do nothing to shared state.
+                _logger.LogDebug("Generic throw on superseded load for track {TrackId} — newer operation owns state, skipping unload", track.EntryKey);
+            }
         }
         finally
         {
@@ -879,13 +886,16 @@ public class StreamingAudioPlayerService : AudioPlayerService, IStreamingPlayerS
             _logger.LogWarning("Refill-failure recovery interop did not succeed: {Error}", recovered.Error);
         }
 
-        // Settle C# into the matching recoverable state: not playing, paused at the target, still loaded.
-        // IsLoaded = true is load-bearing — the "paused-but-loaded" contract lets the listener retry
-        // the seek or pick another track; resetting to unloaded would evict the track identity.
+        // Settle C# into the matching recoverable state: not playing, paused at the target, still loaded
+        // and still in streaming mode. IsLoaded = true and IsStreamingMode = true are both load-bearing —
+        // the "paused-but-loaded" contract lets the listener retry the seek (Seek early-returns when
+        // !IsLoaded || !IsStreamingMode), resume via TogglePlayPause, or pick another track. Resetting
+        // either to false would wedge at least one of the three retry routes (AC6 / Phase 21.3).
         ErrorMessage = userFacingError;
         IsPlaying = false;
         IsPaused = true;
         IsLoaded = true;
+        IsStreamingMode = true;
         CurrentTime = seekPosition;
         IsSeekingBeyondBuffer = false;
         await NotifyStateChanged();

DeepDrftTests/SegmentedStreamLoopTests.cs

@@ -353,6 +353,8 @@ public class SegmentedStreamLoopTests
                 "a truncated segment while cursor < totalLength is a failure: scheduler must be halted via recovery");
             Assert.That(player.IsLoaded, Is.True,
                 "recovery leaves the track loaded so the listener can retry — not torn down to unloaded");
+            Assert.That(player.IsStreamingMode, Is.True,
+                "recovery must restore IsStreamingMode=true so Seek() is not wedged (AC6 / Phase 21.3 retry contract)");
             Assert.That(player.IsPaused, Is.True,
                 "recovery settles into a paused state, not playing");
             Assert.That(player.ErrorMessage, Is.Not.Null.And.Not.Empty,
@@ -381,6 +383,8 @@ public class SegmentedStreamLoopTests
                 "a mid-stream fetch failure must halt the scheduler via recovery, not leave it to drain");
             Assert.That(player.IsLoaded, Is.True,
                 "recovery leaves the track loaded so the listener can retry — not torn down to unloaded");
+            Assert.That(player.IsStreamingMode, Is.True,
+                "recovery must restore IsStreamingMode=true so Seek() is not wedged (AC6 / Phase 21.3 retry contract)");
             Assert.That(player.IsPaused, Is.True,
                 "recovery settles into a paused state, not playing");
             Assert.That(player.ErrorMessage, Is.Not.Null.And.Not.Empty,