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

NotesTests/NoteMapperTests.swift

@@ -54,4 +54,69 @@ struct NoteMapperTests {
         #expect(restored.payload == note.payload)
         #expect(restored.meta.id == note.meta.id)
     }
+
+    // MARK: - Audio columns
+
+    @Test func pendingAudioColumnsRoundTrip() throws {
+        let (container, context) = try makeStore()
+        defer { withExtendedLifetime(container) {} }
+        var ctx = CaptureContext.empty
+        ctx.device = "Watch"
+        let audio = Note.AudioInfo(
+            duration: 30,
+            transcriberDeviceID: "install-42",
+            transcriptionStatus: .pending,
+            transcriptionLocaleID: nil,
+            transcribedAt: nil
+        )
+        let note = Note.create(text: "", source: .transcribed, context: ctx, audio: audio)
+        NoteMapper.upsert(note, relativePath: note.relativePath, into: context)
+
+        let entity = try #require(NoteMapper.fetch(id: note.meta.id.stringValue, in: context))
+        #expect(entity.hasAudio)
+        #expect(entity.audioDuration == 30)
+        #expect(entity.transcriberDeviceID == "install-42")
+        #expect(entity.transcriptionStatusRaw == "pending")
+        #expect(entity.source == .transcribed)
+
+        // A pending audio note carries no `transcribedAt`, so it reconstructs
+        // losslessly (that field is the only one the cache intentionally drops).
+        let restored = try #require(NoteMapper.note(from: entity))
+        #expect(restored.payload == note.payload)
+        #expect(restored.payload.audio == audio)
+    }
+
+    @Test func doneTranscriptionCachesColumnsButNotTranscribedAt() throws {
+        let (container, context) = try makeStore()
+        defer { withExtendedLifetime(container) {} }
+        let audio = Note.AudioInfo(
+            duration: 5,
+            transcriberDeviceID: "install-7",
+            transcriptionStatus: .done,
+            transcriptionLocaleID: "en_US",
+            transcribedAt: Date()
+        )
+        let note = Note.create(text: "Hello there", source: .transcribed, context: .empty, audio: audio)
+        NoteMapper.upsert(note, relativePath: note.relativePath, into: context)
+
+        let entity = try #require(NoteMapper.fetch(id: note.meta.id.stringValue, in: context))
+        #expect(entity.transcriptionStatusRaw == "done")
+        #expect(entity.transcriptionLocaleID == "en_US")
+        // The file is authoritative for the timestamp — the cache doesn't store it.
+        #expect(entity.audio?.transcribedAt == nil)
+        #expect(entity.audio?.transcriptionStatus == .done)
+    }
+
+    @Test func textNoteHasNoAudioColumns() throws {
+        let (container, context) = try makeStore()
+        defer { withExtendedLifetime(container) {} }
+        let note = makeNote()
+        NoteMapper.upsert(note, relativePath: note.relativePath, into: context)
+
+        let entity = try #require(NoteMapper.fetch(id: note.meta.id.stringValue, in: context))
+        #expect(!entity.hasAudio)
+        #expect(entity.audio == nil)
+        #expect(entity.audioDuration == nil)
+        #expect(entity.transcriptionStatusRaw == nil)
+    }
 }