feat: add MenuBarView with start/stop, settings, and error display

MyVoxtral/MyVoxtral/Views/MenuBarView.swift

@@ -0,0 +1,43 @@
+import SwiftUI
+
+struct MenuBarView: View {
+    @ObservedObject var manager: TranscriptionManager
+    @ObservedObject var settings = AppSettings.shared
+    let onShowTranscription: () -> Void
+    let onShowSettings: () -> Void
+
+    var body: some View {
+        VStack(spacing: 4) {
+            Button(manager.isRecording ? "Stop Recording" : "Start Recording") {
+                manager.toggle()
+            }
+            .keyboardShortcut("r")
+
+            if case .error(let msg) = manager.state {
+                Text(msg)
+                    .font(.caption)
+                    .foregroundStyle(.red)
+                    .lineLimit(2)
+                    .padding(.horizontal, 8)
+            }
+
+            Divider()
+
+            Button("Show Transcription") {
+                onShowTranscription()
+            }
+
+            Button("Settings...") {
+                onShowSettings()
+            }
+
+            Divider()
+
+            Button("Quit") {
+                NSApplication.shared.terminate(nil)
+            }
+            .keyboardShortcut("q")
+        }
+        .padding(.vertical, 4)
+    }
+}