Phase 21.3: seek-back-past-window refill + clean refill-failure recovery

Seek-back past the retained tail reuses the existing seek-beyond-buffer
Range path (per-path resolver). A failed refill now halts the scheduler
into a paused-but-loaded state (AC6) instead of a silent false end.

DeepDrftPublic/Interop/audio/index.ts

@@ -131,6 +131,15 @@ const DeepDrftAudio = {
         return player.reinitializeFromOffset(totalStreamLength, seekPosition);
     },
 
+    // Phase 21.3 / AC6: recover into a clean paused-but-loaded state after a window-miss refill
+    // (seek-back past the retained tail) failed its Range fetch or reinit. Prevents the starved
+    // scheduler from firing a silent false end; leaves the track loaded so a retry is possible.
+    recoverFromFailedRefill: (playerId: string, seekPosition: number): AudioResult => {
+        const player = audioPlayers.get(playerId);
+        if (!player) return { success: false, error: 'Player not found' };
+        return player.recoverFromFailedRefill(seekPosition);
+    },
+
     setVolume: (playerId: string, volume: number): AudioResult => {
         const player = audioPlayers.get(playerId);
         if (!player) return { success: false, error: 'Player not found' };