feat: enhance mobile responsiveness with collapsible controls and automation/effects bars

Added comprehensive mobile support for Phase 15 (Polish & Optimization):

**Mobile Layout Enhancements:**
- Track controls now collapsible on mobile with two states:
  - Collapsed: minimal controls with expand chevron, R/M/S buttons, horizontal level meter
  - Expanded: full height fader, pan control, all buttons
- Track collapse buttons added to mobile view (left chevron for track collapse, right chevron for control collapse)
- Master controls collapse button hidden on desktop (lg:hidden)
- Automation and effects bars now available on mobile layout
- Both bars collapsible with eye/eye-off icons, horizontally scrollable when zoomed
- Mobile vertical stacking: controls → waveform → automation → effects per track

**Bug Fixes:**
- Fixed track controls and waveform container height matching on desktop
- Fixed Modal component prop: isOpen → open in all dialog components
- Fixed TypeScript null check for audioBuffer.duration
- Fixed keyboard shortcut category: 'help' → 'view'

**Technical Improvements:**
- Consistent height calculation using trackHeight variable
- Proper responsive breakpoints with Tailwind (sm:640px, lg:1024px)
- Progressive disclosure pattern for mobile controls

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

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

lib/utils/browser-compat.ts

@@ -0,0 +1,133 @@
+/**
+ * Browser compatibility checking utilities
+ */
+
+export interface BrowserCompatibility {
+  isSupported: boolean;
+  missingFeatures: string[];
+  warnings: string[];
+}
+
+/**
+ * Check if all required browser features are supported
+ */
+export function checkBrowserCompatibility(): BrowserCompatibility {
+  const missingFeatures: string[] = [];
+  const warnings: string[] = [];
+
+  // Check if running in browser
+  if (typeof window === 'undefined') {
+    return {
+      isSupported: true,
+      missingFeatures: [],
+      warnings: [],
+    };
+  }
+
+  // Check Web Audio API
+  if (!window.AudioContext && !(window as any).webkitAudioContext) {
+    missingFeatures.push('Web Audio API');
+  }
+
+  // Check IndexedDB
+  if (!window.indexedDB) {
+    missingFeatures.push('IndexedDB');
+  }
+
+  // Check localStorage
+  try {
+    localStorage.setItem('test', 'test');
+    localStorage.removeItem('test');
+  } catch (e) {
+    missingFeatures.push('LocalStorage');
+  }
+
+  // Check Canvas API
+  const canvas = document.createElement('canvas');
+  if (!canvas.getContext || !canvas.getContext('2d')) {
+    missingFeatures.push('Canvas API');
+  }
+
+  // Check MediaDevices API (for recording)
+  if (!navigator.mediaDevices || !navigator.mediaDevices.getUserMedia) {
+    warnings.push('Microphone recording not supported (requires HTTPS or localhost)');
+  }
+
+  // Check File API
+  if (!window.File || !window.FileReader || !window.FileList || !window.Blob) {
+    missingFeatures.push('File API');
+  }
+
+  // Check AudioWorklet support (optional)
+  if (window.AudioContext && !AudioContext.prototype.hasOwnProperty('audioWorklet')) {
+    warnings.push('AudioWorklet not supported (some features may have higher latency)');
+  }
+
+  // Check OfflineAudioContext
+  if (!window.OfflineAudioContext && !(window as any).webkitOfflineAudioContext) {
+    missingFeatures.push('OfflineAudioContext (required for audio processing)');
+  }
+
+  return {
+    isSupported: missingFeatures.length === 0,
+    missingFeatures,
+    warnings,
+  };
+}
+
+/**
+ * Get user-friendly browser name
+ */
+export function getBrowserInfo(): { name: string; version: string } {
+  // Check if running in browser
+  if (typeof window === 'undefined' || typeof navigator === 'undefined') {
+    return { name: 'Unknown', version: 'Unknown' };
+  }
+
+  const userAgent = navigator.userAgent;
+  let name = 'Unknown';
+  let version = 'Unknown';
+
+  if (userAgent.indexOf('Chrome') > -1 && userAgent.indexOf('Edg') === -1) {
+    name = 'Chrome';
+    const match = userAgent.match(/Chrome\/(\d+)/);
+    version = match ? match[1] : 'Unknown';
+  } else if (userAgent.indexOf('Edg') > -1) {
+    name = 'Edge';
+    const match = userAgent.match(/Edg\/(\d+)/);
+    version = match ? match[1] : 'Unknown';
+  } else if (userAgent.indexOf('Firefox') > -1) {
+    name = 'Firefox';
+    const match = userAgent.match(/Firefox\/(\d+)/);
+    version = match ? match[1] : 'Unknown';
+  } else if (userAgent.indexOf('Safari') > -1 && userAgent.indexOf('Chrome') === -1) {
+    name = 'Safari';
+    const match = userAgent.match(/Version\/(\d+)/);
+    version = match ? match[1] : 'Unknown';
+  }
+
+  return { name, version };
+}
+
+/**
+ * Check if browser version meets minimum requirements
+ */
+export function checkMinimumVersion(): boolean {
+  const { name, version } = getBrowserInfo();
+  const versionNum = parseInt(version, 10);
+
+  const minimumVersions: Record<string, number> = {
+    Chrome: 90,
+    Edge: 90,
+    Firefox: 88,
+    Safari: 14,
+  };
+
+  const minVersion = minimumVersions[name];
+  if (!minVersion) {
+    // Unknown browser, assume it's ok
+    return true;
+  }
+
+  return versionNum >= minVersion;
+}