Add Text-to-Speech and Speech-to-Text features

- Add TTS service using AVSpeechSynthesizer for voice output
- Add STT service using SpeechAnalyzer (macOS 26) for transcription
- Add voice input (microphone) button in chat with recording level indicator
- Add speak button on assistant messages for TTS playback
- Add language toggle (EN-CA/FR-CA) for bilingual speech recognition
- Fix Swift 6 strict concurrency issues in audio callbacks
- Update proto schema with TTS/STT message types and RPCs
- Update gRPC provider with speech service endpoints

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Sources/AppleIntelligenceApp/Views/ChatView.swift

@@ -23,7 +23,11 @@ struct ChatView: View {
                     ScrollView {
                         LazyVStack(spacing: 12) {
                             ForEach(viewModel.messages) { message in
-                                MessageBubble(message: message)
+                                MessageBubble(
+                                    message: message,
+                                    isSpeaking: viewModel.speakingMessageId == message.id,
+                                    onSpeak: { viewModel.speakMessage(message) }
+                                )
                                     .id(message.id)
                             }
                         }
@@ -286,6 +290,45 @@ struct ChatView: View {
             .buttonStyle(.plain)
             .help("Paste image from clipboard")
 
+            // Language toggle for speech recognition
+            Button {
+                // Toggle between en-CA and fr-CA
+                let newLang = viewModel.detectedLanguage == "en-CA" ? "fr-CA" : "en-CA"
+                viewModel.switchLanguage(to: newLang)
+            } label: {
+                Text(viewModel.detectedLanguage == "fr-CA" ? "FR" : "EN")
+                    .font(.caption.bold())
+                    .foregroundStyle(.secondary)
+                    .frame(width: 24, height: 24)
+                    .background(
+                        RoundedRectangle(cornerRadius: 4)
+                            .fill(Color.secondary.opacity(0.1))
+                    )
+            }
+            .buttonStyle(.plain)
+            .help("Speech language: \(viewModel.detectedLanguage) (click to toggle)")
+
+            // Microphone button for voice input
+            Button {
+                viewModel.toggleRecording()
+            } label: {
+                ZStack {
+                    if viewModel.isRecording {
+                        // Recording indicator with level
+                        Circle()
+                            .fill(Color.red.opacity(0.3))
+                            .frame(width: 28 + CGFloat(viewModel.recordingLevel) * 10,
+                                   height: 28 + CGFloat(viewModel.recordingLevel) * 10)
+                            .animation(.easeInOut(duration: 0.1), value: viewModel.recordingLevel)
+                    }
+                    Image(systemName: viewModel.isRecording ? "mic.fill" : "mic")
+                        .font(.title3)
+                        .foregroundStyle(viewModel.isRecording ? .red : .secondary)
+                }
+            }
+            .buttonStyle(.plain)
+            .help(viewModel.isRecording ? "Stop recording" : "Voice input")
+
             TextField("Message...", text: $viewModel.inputText, axis: .vertical)
                 .textFieldStyle(.plain)
                 .lineLimit(1...5)
@@ -386,6 +429,8 @@ struct RecentImageThumbnail: View {
 
 struct MessageBubble: View {
     let message: ChatMessage
+    var isSpeaking: Bool = false
+    var onSpeak: (() -> Void)? = nil
     @State private var showCopied = false
 
     var body: some View {
@@ -419,10 +464,23 @@ struct MessageBubble: View {
                     }
                 }
 
-                // Copy button for assistant messages
+                // Action buttons for assistant messages
                 if message.role == .assistant && !message.content.isEmpty && !message.isStreaming {
-                    HStack {
-                        Spacer()
+                    HStack(spacing: 12) {
+                        // Speaker button for TTS
+                        Button {
+                            onSpeak?()
+                        } label: {
+                            HStack(spacing: 4) {
+                                Image(systemName: isSpeaking ? "stop.fill" : "speaker.wave.2")
+                                Text(isSpeaking ? "Stop" : "Speak")
+                            }
+                            .font(.caption)
+                            .foregroundStyle(isSpeaking ? .red : .secondary)
+                        }
+                        .buttonStyle(.plain)
+
+                        // Copy button
                         Button {
                             NSPasteboard.general.clearContents()
                             NSPasteboard.general.setString(message.content, forType: .string)
@@ -439,6 +497,8 @@ struct MessageBubble: View {
                             .foregroundStyle(.secondary)
                         }
                         .buttonStyle(.plain)
+
+                        Spacer()
                     }
                     .padding(.top, 2)
                 }