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/NoteEntity.swift

@@ -30,6 +30,17 @@ final class NoteEntity {
     var timeZoneID: String?
     var device: String?
 
+    // Flattened AudioInfo — nil columns mean a plain text note. `hasAudio` is
+    // stored rather than derived from `audioDuration` so a zero-length recording
+    // is still recognizably a voice note. `transcribedAt` is deliberately not
+    // cached (the file is authoritative for that timestamp), so a cache-only
+    // reconstruction of a completed note has a nil `transcribedAt`.
+    var hasAudio: Bool = false
+    var audioDuration: Double?
+    var transcriptionStatusRaw: String?
+    var transcriptionLocaleID: String?
+    var transcriberDeviceID: String?
+
     init(id: String, jsonRelativePath: String) {
         self.id = id
         self.jsonRelativePath = jsonRelativePath
@@ -70,6 +81,31 @@ extension NoteEntity {
         Note.Source(rawValue: sourceRaw) ?? .typed
     }
 
+    /// Reconstructs `AudioInfo` from the flattened columns (nil for a text
+    /// note). `transcribedAt` is not cached, so it comes back nil even for a
+    /// completed transcription — acceptable for the cache-only offline fallback,
+    /// where the file (which carries it) simply wasn't reachable.
+    var audio: Note.AudioInfo? {
+        get {
+            guard hasAudio else { return nil }
+            return Note.AudioInfo(
+                duration: audioDuration ?? 0,
+                transcriberDeviceID: transcriberDeviceID ?? "",
+                transcriptionStatus: transcriptionStatusRaw
+                    .flatMap(Note.TranscriptionStatus.init(rawValue:)) ?? .pending,
+                transcriptionLocaleID: transcriptionLocaleID,
+                transcribedAt: nil
+            )
+        }
+        set {
+            hasAudio = newValue != nil
+            audioDuration = newValue?.duration
+            transcriberDeviceID = newValue?.transcriberDeviceID
+            transcriptionStatusRaw = newValue?.transcriptionStatus.rawValue
+            transcriptionLocaleID = newValue?.transcriptionLocaleID
+        }
+    }
+
     /// First line of the text, used as the display title.
     var title: String {
         text.split(separator: "\n", omittingEmptySubsequences: true)