lotus(#3): harden audio-inject per review

- resume() the AudioContext (host postMessage isn't a gesture) so the clip
  isn't silent; warn if it stays suspended (HIGH).
- Close the AudioContext on decode failure (no context leak) (MED).
- Abort in-flight clips on teardown (unmount/vm-change/leave) so audio
  doesn't keep blasting to peers (MED).
- Stop the cloned MediaStreamTrack when a room publish fails (MED).
- Validate url is https/blob and fetch with credentials:omit, mode:cors
  (MED security).
- Guard against NaN clip duration; fix stale enum doc comment.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lotus/lotusActions.ts

@@ -21,7 +21,7 @@ export enum LotusWidgetActions {
   CallState = "io.lotus.call_state",
   /** toWidget: pin/spotlight (or clear, with userId=null) a participant. */
   FocusParticipant = "io.lotus.focus_participant",
-  /** toWidget: mix an audio clip into the local published mic track. */
+  /** toWidget: play an audio clip into the call as a separate published track. */
   InjectAudio = "io.lotus.inject_audio",
   /** toWidget: set audio/screenshare encoding quality (bitrate/framerate). */
   SetQuality = "io.lotus.set_quality",