feat(fetcher): add configureNativeFetcher cross-platform API

Add configureNativeFetcher() plugin method to enable TypeScript configuration
of native fetchers with API credentials. This provides a cross-platform
mechanism for passing configuration from JavaScript to native code without
relying on platform-specific storage.

- Add configure() method to NativeNotificationContentFetcher interface
  (optional, defaults to no-op for fetchers that don't need config)
- Add configureNativeFetcher plugin method in DailyNotificationPlugin
- Add TypeScript definitions and comprehensive JSDoc
- Create NATIVE_FETCHER_CONFIGURATION.md documentation
- Update TestNativeFetcher to use real API endpoint (10.0.2.2:3000)
- Update DemoNativeFetcher Javadoc explaining configure() is optional
- Add configureNativeFetcher() call to demo app's configurePlugin()

Enables host apps to configure native fetchers from TypeScript, keeping
the interface consistent across Android, iOS, and web platforms.

src/definitions.ts

@@ -314,6 +314,71 @@ export interface DailyNotificationPlugin {
   // Configuration methods
   configure(options: ConfigureOptions): Promise<void>;
   
+  /**
+   * Configure native fetcher with API credentials (cross-platform)
+   * 
+   * This method provides a cross-platform mechanism for passing API credentials
+   * from TypeScript/JavaScript code to native fetcher implementations. The
+   * configuration is passed directly without using platform-specific storage
+   * mechanisms, keeping the interface consistent across Android, iOS, and web.
+   * 
+   * **Why this exists:**
+   * - Native fetchers run in background workers (WorkManager/BGTaskScheduler)
+   * - Background workers cannot access JavaScript variables or Capacitor bridge
+   * - This method provides direct injection without storage dependencies
+   * 
+   * **When to call:**
+   * - After app startup, once API credentials are available
+   * - After user login/authentication, when activeDid changes
+   * - When API server URL changes (dev/staging/production)
+   * 
+   * **Prerequisites:**
+   * - Native fetcher must be registered in `Application.onCreate()` (Android)
+   *   or `AppDelegate.didFinishLaunching()` (iOS) BEFORE calling this method
+   * - Should be called before any background fetches occur
+   * 
+   * **Thread Safety:**
+   * - Safe to call from any thread (main thread or background)
+   * - Configuration changes take effect immediately for subsequent fetches
+   * - Native implementations should use `volatile` fields for thread safety
+  เร็ * 
+   * **Example:**
+   * ```typescript
+   * import { DailyNotification } from '@capacitor-community/daily-notification';
+   * 
+   * await DailyNotification.configureNativeFetcher({
+   *   apiBaseUrl: 'http://10.0.2.2:3000',  // Android emulator → host localhost
+   *   activeDid: 'did:ethr:0x0000694B58C2cC69658993A90D3840C560f2F51F',
+   *   jwtSecret: 'test-jwt-secret-for-development'
+   * });
+   * ```
+   * 
+   * **Error Handling:**
+   * - Rejects if required parameters are missing
+   * - Rejects if no native fetcher is registered
+   * - Rejects if native fetcher's `configure()` throws exception
+   * 
+   * @param options Configuration options:
+   *                - `apiBaseUrl` (required): Base URL for API server.
+   *                  - Android emulator: `"http://10.0.2.2:3000"` (maps to host localhost:3000)
+   *                  - iOS simulator: `"http://localhost:3000"`
+   *                  - Production: `"https://api.timesafari.com"`
+   *                - `activeDid` (required): Active DID for authentication.
+   *                  Format: `"did:ethr:0x..."`. Used as JWT issuer/subject.
+   *                - `jwtSecret` (required): JWT secret for signing tokens.
+   *                  **Keep secure in production!** Consider using secure storage.
+   * 
+   * @throws {Error} If configuration fails (missing params, no fetcher registered, etc.)
+   * 
+   * @see {@link https://github.com/timesafari/daily-notification-plugin/blob/main/docs/NATIVE_FETCHER_CONFIGURATION.md | Native Fetcher Configuration Guide}
+   *      for complete documentation and examples
+   */
+  configureNativeFetcher(options: {
+    apiBaseUrl: string;
+    activeDid: string;
+    jwtSecret: string;
+  }): Promise<void>;
+  
   // Rolling window management
   maintainRollingWindow(): Promise<void>;
   getRollingWindowStats(): Promise<{