Split audio update into early/late phases, add asset<->stream type map, switch volume/pan to float, add stream loop limit

- audioUpdate()/audioMixerUpdate() split into Early (before rendering, per-stream buffering) and Late (end of frame, starts newly-queued mixer sounds) phases, wired into engineUpdate() around displayUpdate(); mixer is now actually initialized/disposed/updated from audio.c.
- New src/dusk/audio/stream/audiostreamtype.{h,c}: asset-loader-type <-> audio-stream-type map (with file extension), plus audioStreamAssetTypeForPath()/audioStreamTypeForAssetType()/audioStreamAssetTypeForStreamType() lookups.
- audiostream_t/audiomixerchanneldata_t volume and directionality/pan switched from integer (0-0xFF / -128..127) to float (0.0-1.0 / -1.0..1.0), removing the manual scaling each platform backend had to do.
- audiostream_t gains loopLimit/loopRestartCount so a stream can be told to stop (fire onEnd) after a fixed number of loop restarts instead of looping forever; wired into the shared restart path (Linux/Dolphin) and PSP's own read-ahead loop decision.

Built and verified on Linux, PSP (Docker) and GameCube (Docker).

Co-Authored-By: Claude Sonnet 5 <[email protected]>

src/dusklinux/audio/audiostreamlinux.c

@@ -191,7 +191,7 @@ errorret_t audioStreamLinuxFeed(audiostream_t *stream) {
   const size_t bytesRead = framesRead * frameSize;
   int queued;
 
-  if(stream->volume == 0xFF) {
+  if(stream->volume >= 1.0f) {
     // Nothing to mix at full volume - queue the window directly instead of
     // allocating/zeroing a same-size scratch buffer just to copy it in.
     queued = SDL_QueueAudio(stream->platform.device, chunk, (Uint32) bytesRead);
@@ -200,7 +200,7 @@ errorret_t audioStreamLinuxFeed(audiostream_t *stream) {
     memoryZero(mixed, bytesRead);
     SDL_MixAudioFormat(
       mixed, (uint8_t *) chunk, AUDIO_S16SYS, (Uint32) bytesRead,
-      (stream->volume * SDL_MIX_MAXVOLUME) / 0xFF
+      (int) (stream->volume * SDL_MIX_MAXVOLUME)
     );
     queued = SDL_QueueAudio(stream->platform.device, mixed, (Uint32) bytesRead);
     memoryFree(mixed);