feat: add media converter app and fix compilation errors

lib/media/storage/settings.ts

@@ -0,0 +1,73 @@
+export interface UserSettings {
+  // Quality preferences
+  defaultQualityPreset: 'high-quality' | 'balanced' | 'small-file' | 'web-optimized';
+
+  // Behavior preferences
+  autoStartConversion: boolean;
+  showConversionHistory: boolean;
+  clearHistoryOnReset: boolean;
+
+  // Default formats (optional)
+  defaultVideoFormat?: string;
+  defaultAudioFormat?: string;
+  defaultImageFormat?: string;
+}
+
+const SETTINGS_KEY = 'convert-ui-settings';
+
+const DEFAULT_SETTINGS: UserSettings = {
+  defaultQualityPreset: 'balanced',
+  autoStartConversion: false,
+  showConversionHistory: true,
+  clearHistoryOnReset: false,
+};
+
+/**
+ * Get user settings from localStorage
+ */
+export function getSettings(): UserSettings {
+  if (typeof window === 'undefined') return DEFAULT_SETTINGS;
+
+  try {
+    const stored = localStorage.getItem(SETTINGS_KEY);
+    if (!stored) return DEFAULT_SETTINGS;
+
+    const settings = JSON.parse(stored);
+    return { ...DEFAULT_SETTINGS, ...settings };
+  } catch (error) {
+    console.error('Failed to load settings:', error);
+    return DEFAULT_SETTINGS;
+  }
+}
+
+/**
+ * Save user settings to localStorage
+ */
+export function saveSettings(settings: Partial<UserSettings>): void {
+  if (typeof window === 'undefined') return;
+
+  try {
+    const current = getSettings();
+    const updated = { ...current, ...settings };
+    localStorage.setItem(SETTINGS_KEY, JSON.stringify(updated));
+
+    // Dispatch custom event for settings updates
+    window.dispatchEvent(new CustomEvent('settingsUpdated', { detail: updated }));
+  } catch (error) {
+    console.error('Failed to save settings:', error);
+  }
+}
+
+/**
+ * Reset settings to defaults
+ */
+export function resetSettings(): void {
+  if (typeof window === 'undefined') return;
+
+  try {
+    localStorage.setItem(SETTINGS_KEY, JSON.stringify(DEFAULT_SETTINGS));
+    window.dispatchEvent(new CustomEvent('settingsUpdated', { detail: DEFAULT_SETTINGS }));
+  } catch (error) {
+    console.error('Failed to reset settings:', error);
+  }
+}