Add Psytrance Visualizer macOS app with Metal rendering

A complete audio-reactive visualizer for psytrance music featuring:

Audio Analysis (DSPEngine):
- FFT spectrum analysis via Accelerate/vDSP
- 64-band Mel spectrogram
- Sub-bass energy extraction (<100Hz)
- Automatic sidechain pump detection
- Harmonic-to-Noise ratio (HNR) calculation
- Peak/transient detection

8 Visualization Modes (Metal Shaders):
1. FFT Classic - Frequency spectrum bars with glow
2. Mel Spectrogram - Waterfall display
3. Sub-Bass - Pulsating rings
4. Sidechain Pump - Breathing zoom effect
5. Harmonic/Noise - Geometric vs chaotic particles
6. Mandelbrot - Audio-reactive fractal zoom
7. Tunnel Warp - Infinite tunnel with distortion
8. DMT Geometry - Sacred geometry patterns

Features:
- Selectable audio input device (BlackHole support)
- Configurable buffer size (512/1024)
- Reactivity slider for visual intensity
- Auto-hiding control panel
- Fullscreen support with keyboard shortcuts (1-8, F, ESC)
- Persistent settings via UserDefaults
- Psytrance-inspired neon/UV color palette

PsytranceVisualizer/App/AppDelegate.swift

@@ -0,0 +1,120 @@
+//
+//  AppDelegate.swift
+//  PsytranceVisualizer
+//
+//  Application delegate handling app lifecycle
+//
+
+import AppKit
+import AVFoundation
+
+/// Application delegate
+final class AppDelegate: NSObject, NSApplicationDelegate {
+    // MARK: - Properties
+
+    private var mainWindowController: MainWindowController?
+
+    // MARK: - App Lifecycle
+
+    func applicationDidFinishLaunching(_ notification: Notification) {
+        // Request microphone permission
+        requestMicrophonePermission()
+
+        // Create and show main window
+        mainWindowController = MainWindowController()
+        mainWindowController?.showWindow(nil)
+        mainWindowController?.window?.makeKeyAndOrderFront(nil)
+
+        // Activate the application
+        NSApp.activate(ignoringOtherApps: true)
+
+        print("[AppDelegate] Application launched")
+    }
+
+    func applicationWillTerminate(_ notification: Notification) {
+        // Save settings
+        SettingsManager.shared.saveNow()
+
+        print("[AppDelegate] Application terminating")
+    }
+
+    func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
+        return true
+    }
+
+    func applicationSupportsSecureRestorableState(_ app: NSApplication) -> Bool {
+        return true
+    }
+
+    // MARK: - Permissions
+
+    private func requestMicrophonePermission() {
+        switch AVCaptureDevice.authorizationStatus(for: .audio) {
+        case .authorized:
+            print("[AppDelegate] Microphone access already authorized")
+
+        case .notDetermined:
+            AVCaptureDevice.requestAccess(for: .audio) { granted in
+                if granted {
+                    print("[AppDelegate] Microphone access granted")
+                } else {
+                    print("[AppDelegate] Microphone access denied")
+                    self.showMicrophonePermissionAlert()
+                }
+            }
+
+        case .denied, .restricted:
+            print("[AppDelegate] Microphone access denied or restricted")
+            showMicrophonePermissionAlert()
+
+        @unknown default:
+            break
+        }
+    }
+
+    private func showMicrophonePermissionAlert() {
+        DispatchQueue.main.async {
+            let alert = NSAlert()
+            alert.messageText = "Microphone Access Required"
+            alert.informativeText = "Psytrance Visualizer needs access to your audio input to visualize music. Please enable microphone access in System Preferences > Security & Privacy > Privacy > Microphone."
+            alert.alertStyle = .warning
+            alert.addButton(withTitle: "Open System Preferences")
+            alert.addButton(withTitle: "Cancel")
+
+            if alert.runModal() == .alertFirstButtonReturn {
+                if let url = URL(string: "x-apple.systempreferences:com.apple.preference.security?Privacy_Microphone") {
+                    NSWorkspace.shared.open(url)
+                }
+            }
+        }
+    }
+
+    // MARK: - Menu Actions
+
+    @IBAction func showAbout(_ sender: Any) {
+        let alert = NSAlert()
+        alert.messageText = "Psytrance Visualizer"
+        alert.informativeText = """
+        An audio-reactive visualizer for psytrance music.
+
+        8 Visualization Modes:
+        1 - FFT Classic
+        2 - Mel Spectrogram
+        3 - Sub-Bass
+        4 - Sidechain Pump
+        5 - Harmonic/Noise
+        6 - Mandelbrot
+        7 - Tunnel Warp
+        8 - DMT Geometry
+
+        Keyboard Shortcuts:
+        1-8: Switch visualization mode
+        F: Toggle fullscreen
+        ESC: Exit fullscreen
+
+        Tip: Use a virtual audio device like BlackHole to route system audio.
+        """
+        alert.alertStyle = .informational
+        alert.runModal()
+    }
+}