Replace broken per-segment Opus decode with WebCodecs AudioDecoder streaming pipeline

DeepDrftPublic/Interop/audio/IFormatDecoder.ts

@@ -1,5 +1,3 @@
-import { OpusSeekData } from './OpusSidecar.js';
-
 /**
  * FormatInfo: parsed header data needed to stream and seek an audio file.
  * Populated by IFormatDecoder.tryParseHeader; used by StreamDecoder throughout playback.
@@ -38,10 +36,10 @@ export interface FormatInfo {
      * MP3 VBR: Xing/VBRI TOC (100-entry Uint8Array, values are file-percentage * 255).
      * FLAC: SeekTable (array of {sampleNumber: number, streamOffset: number} — stream_offset
      *        is bytes from the start of audio frames, i.e. after all metadata blocks).
-     * Opus: OpusSeekData — the precomputed granule->byte index + OpusHead/OpusTags setup bytes,
-     *        parsed from the sidecar artifact (NOT byteRate math; see OpusFormatDecoder).
+     * Opus does NOT flow through this seam — it uses the WebCodecs IStreamingDecoder path and resolves
+     * seek offsets via OpusSidecar.resolveOpusByteOffset, not FormatInfo.seekData.
      */
-    seekData?: Mp3VbrSeekData | FlacSeekData | OpusSeekData | null;
+    seekData?: Mp3VbrSeekData | FlacSeekData | null;
 }
 
 export interface Mp3VbrSeekData {