Implement Phase 1: Global hotkey, HUD, and audio capture

Add complete listening UX without STT:
- Global hotkey manager with ⌘⇧V, push-to-talk and toggle modes
- Floating HUD with real-time RMS audio visualization
- AVAudioEngine capture with 16kHz mono PCM conversion
- 10-minute dictation timeout with ESC cancellation
- Optional start/stop sounds and microphone permissions
- Permission management for accessibility and input monitoring

All Phase 1 acceptance criteria met.

Sources/App/MenuWhisperApp.swift

@@ -0,0 +1,64 @@
+import SwiftUI
+import CoreUtils
+
+@main
+struct MenuWhisperApp: App {
+    @StateObject private var appController = AppController()
+
+    var body: some Scene {
+        MenuBarExtra("Menu-Whisper", systemImage: "mic") {
+            MenuBarContentView()
+                .environmentObject(appController)
+                .onAppear {
+                    appController.start()
+                }
+        }
+    }
+}
+
+struct MenuBarContentView: View {
+    @EnvironmentObject var appController: AppController
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 4) {
+            Text("Menu-Whisper")
+                .font(.headline)
+
+            Text(appController.currentState.displayName)
+                .font(.subheadline)
+                .foregroundColor(stateColor)
+
+            if appController.currentState == .listening {
+                Text("Press ⌘⇧V or Esc to stop")
+                    .font(.caption)
+                    .foregroundColor(.secondary)
+            }
+
+            Divider()
+
+            Button("Preferences...") {
+                // TODO: Open preferences window in Phase 4
+            }
+
+            Button("Quit") {
+                NSApplication.shared.terminate(nil)
+            }
+        }
+        .padding(.horizontal, 4)
+    }
+
+    private var stateColor: Color {
+        switch appController.currentState {
+        case .idle:
+            return .primary
+        case .listening:
+            return .blue
+        case .processing:
+            return .orange
+        case .injecting:
+            return .green
+        case .error:
+            return .red
+        }
+    }
+}