feat(phase3): implement Background Enhancement & TimeSafari Coordination

- Enhanced Android DailyNotificationScheduler with comprehensive TimeSafari coordination
- Implemented app lifecycle handling for TimeSafari PlatformServiceMixin integration
- Enhanced Android DailyNotificationPlugin with coordinateBackgroundTasks and lifecycle events
- Enhanced Android DailyNotificationFetchWorker with WorkManager coordination constraints
- Enhanced Web platform with visibility change and window lifecycle coordination
- Added comprehensive Phase 3 TypeScript interfaces and type definitions
- Implemented background execution constraints and coordination reporting
- Added app foreground/background detection with activeDid change coordination
- Enhanced state synchronization between plugin and TimeSafari host
- Implemented notification throttling and coordination pause/resume mechanisms

Phase 3 delivers:
✅ Android WorkManager coordination with PlatformServiceMixin
✅ Android app lifecycle event handling (background/foreground/resumed/paused)
✅ Android background task coordination with constraints (low power mode, activeDid changes)
✅ Web platform visibility and window lifecycle coordination
✅ Web sessionStorage-based coordination state persistence
✅ Comprehensive Phase 3 TypeScript interfaces (EnhancedDailyNotificationPlugin, CoordinationStatus, etc.)
✅ Background execution constraint validation
✅ Cross-platform TimeSafari state synchronization
✅ Coordination reporting and debugging capabilities
✅ App lifecycle-aware activeDid change detection and recovery

Ready for Phase 4: Advanced Features & TimeSafari Integration

src/definitions.ts

@@ -550,4 +550,140 @@ export interface ActiveDidChangeEvent {
   activeDid: string;
   timestamp: number;
   source: 'host' | 'plugin';
-};
+};
+
+// MARK: - Phase 3: TimeSafari Background Coordination Interfaces
+
+/**
+ * Phase 3: Extended DailyNotificationPlugin interface with TimeSafari coordination
+ */
+export interface EnhancedDailyNotificationPlugin extends DailyNotificationPlugin {
+  // Phase 1: ActiveDid Management (already extended in parent)
+  
+  // Phase 3: TimeSafari Background Coordination
+  coordinateBackgroundTasks(): Promise<void>;
+  handleAppLifecycleEvent(event: AppLifecycleEvent): Promise<void>;
+  getCoordinationStatus(): Promise<CoordinationStatus>;
+}
+
+/**
+ * Phase 3: App lifecycle events for TimeSafari coordination
+ */
+export type AppLifecycleEvent = 
+  | 'app_background'
+  | 'app_foreground' 
+  | 'app_resumed'
+  | 'app_paused'
+  | 'app_visibility_change'
+  | 'app_hidden'
+  | 'app_visible'
+  | 'app_blur'
+  | 'app_focus';
+
+/**
+ * Phase 3: Coordination status for debugging and monitoring
+ */
+export interface CoordinationStatus {
+  platform: 'android' | 'ios' | 'web' | 'electron';
+  coordinationActive: boolean;
+  coordinationPaused: boolean;
+  autoSync?: boolean;
+  appBackgrounded?: boolean;
+  appHidden?: boolean;
+  visibilityState?: DocumentVisibilityState;
+  focused?: boolean;
+  lastActiveDidChange?: number;
+  lastCoordinationTimestamp?: number;
+  lastAppBackgrounded?: number;
+  lastAppForegrounded?: number;
+  lastCoordinationSuccess?: number;
+  lastCoordinationFailure?: number;
+  coordinationErrors?: string[];
+  activeDidTracking?: string;
+}
+
+/**
+ * Phase 3: PlatformServiceMixin coordination configuration
+ */
+export interface PlatformServiceMixinConfig {
+  enableAutoCoordination?: boolean;
+  coordinationTimeout?: number; // Max time for coordination attempts
+  enableLifecycleEvents?: boolean;
+  enableBackgroundSync?: boolean;
+  enableStatePersistence?: boolean;
+  coordinationGracePeriod?: number; // Grace period for coordination
+  eventHandlers?: {
+    [K in AppLifecycleEvent]?: () => Promise<void>;
+  };
+}
+
+/**
+ * Phase 3: WorkManager coordination data
+ */
+export interface WorkManagerCoordinationData {
+  timesafariCoordination: boolean;
+  coordinationTimestamp: number;
+  activeDidTracking: string;
+  platformCoordinationVersion?: number;
+  coordinationTimeouts?: {
+    maxCoordinationAge: number;
+    maxExecutionTime: number;
+    maxRetryAge: number;
+  };
+}
+
+/**
+ * Phase 3: Background execution constraints
+ */
+export interface BackgroundExecutionConstraints {
+  devicePowerMode?: 'normal' | 'low_power' | 'critical';
+  appForegroundState?: 'foreground' | 'background' | 'inactive';
+  activeDidStability?: 'stable' | 'changing' | 'unknown';
+  coordinationFreshness?: 'fresh' | 'stale' | 'expired';
+  networkAvailability?: 'cellular' | 'wifi' | 'offline';
+  batteryLevel?: 'high' | 'medium' | 'low' | 'critical';
+}
+
+/**
+ * Phase 3: Coordination report
+ */
+export interface CoordinationReport {
+  success: boolean;
+  operation: string;
+  duration: number;
+  constraints: BackgroundExecutionConstraints;
+  errors?: string[];
+  timestamp: number;
+  activeDid?: string;
+  authUsed: boolean;
+  platformSpecific?: Record<string, any>;
+}
+
+/**
+ * Phase 3: TimeSafari state synchronization data
+ */
+export interface TimeSafariSyncData {
+  authenticationState: {
+    activeDid: string;
+    jwtExpiration?: number;
+    tokenRefreshNeeded: boolean;
+  };
+  notificationState: {
+    lastDelivery: number;
+    lastDeliveryId?: string;
+    pendingDeliveries: string[];
+  };
+  backgroundTaskState: {
+    lastBackgroundExecution: number;
+    lastCoordinationSuccess: number;
+    pendingCoordinationTasks: string[];
+  };
+  activeDidHistory: {
+    changes: Array<{
+      did: string;
+      timestamp: number;
+      source: string;
+    }>;
+    pendingUpdates: string[];
+  };
+}