Add voice notes: on-device transcription, multi-language, watch capture

- Schema v2: Note.AudioInfo, .m4a sidecar next to the note JSON in iCloud
- AudioRecorderService (iOS/macOS) + SpeechAnalyzer transcription pipeline
  with enabled-language set and confidence-based auto-pick, re-transcribe menu
- Settings > Transcription > Languages with asset download/reserve handling
- watchOS app + accessory complication: one-button recorder, WCSession
  transferFile to phone, WatchInbox staging, direct-upsert ingestion
- Player UI, transcription status chips, quick-capture mic in notes list
- Version 0.2, changelog + README updated

Notes/Model/NoteMapper.swift

@@ -35,6 +35,7 @@ enum NoteMapper {
         entity.modifiedAt = note.meta.modifiedAt
         entity.jsonRelativePath = relativePath
         entity.context = note.payload.context
+        entity.audio = note.payload.audio
     }
 
     /// Near-lossless reconstruction from the cache, used only as the offline
@@ -52,7 +53,8 @@ enum NoteMapper {
                 text: entity.text,
                 source: entity.source,
                 tags: entity.tags,
-                context: entity.context
+                context: entity.context,
+                audio: entity.audio
             )
         )
     }