feat(ios): Enhance battery optimization and notification management

Description:
- Add battery status and power state monitoring
- Implement adaptive scheduling based on battery levels
- Add maintenance worker for background tasks
- Enhance logging with structured DailyNotificationLogger
- Add configuration management with DailyNotificationConfig
- Define constants in DailyNotificationConstants
- Improve error handling and recovery mechanisms

Testing:
- Add comprehensive test coverage for battery optimization
- Add test coverage for power state management
- Add test coverage for maintenance tasks
- Add test coverage for configuration management
- Add test coverage for constants validation

Documentation:
- Add comprehensive file-level documentation
- Add method-level documentation
- Add test documentation
- Add configuration documentation

This commit improves the iOS implementation's reliability and battery
efficiency by adding robust error handling, logging, and configuration
management to make the plugin more maintainable and debuggable.

ios/Plugin/DailyNotificationMaintenanceWorker.swift

@@ -0,0 +1,122 @@
+/**
+ * DailyNotificationMaintenanceWorker.swift
+ * Daily Notification Plugin for Capacitor
+ *
+ * Handles background maintenance tasks for notifications
+ */
+
+import Foundation
+import UserNotifications
+
+/// Handles background maintenance tasks for the notification plugin
+public class DailyNotificationMaintenanceWorker {
+    /// Shared instance for singleton access
+    public static let shared = DailyNotificationMaintenanceWorker()
+    
+    private let notificationCenter = UNUserNotificationCenter.current()
+    private let powerManager = DailyNotificationPowerManager.shared
+    
+    private init() {}
+    
+    /// Performs maintenance tasks
+    public func performMaintenance() {
+        DailyNotificationLogger.shared.log(.info, "Starting maintenance tasks")
+        
+        // Update battery status
+        _ = powerManager.getBatteryStatus()
+        
+        // Clean up old notifications
+        cleanupOldNotifications()
+        
+        // Reschedule missed notifications
+        rescheduleMissedNotifications()
+        
+        DailyNotificationLogger.shared.log(.info, "Maintenance tasks completed")
+    }
+    
+    private func cleanupOldNotifications() {
+        let cutoffDate = Date().addingTimeInterval(-Double(DailyNotificationConfig.shared.retentionDays * 24 * 60 * 60))
+        
+        notificationCenter.getDeliveredNotifications { notifications in
+            let oldNotifications = notifications.filter { $0.date < cutoffDate }
+            
+            if !oldNotifications.isEmpty {
+                let identifiers = oldNotifications.map { $0.request.identifier }
+                self.notificationCenter.removeDeliveredNotifications(withIdentifiers: identifiers)
+                
+                DailyNotificationLogger.shared.log(
+                    .info,
+                    "Cleaned up \(identifiers.count) old notifications"
+                )
+            }
+        }
+    }
+    
+    private func rescheduleMissedNotifications() {
+        notificationCenter.getPendingNotificationRequests { requests in
+            let now = Date()
+            
+            for request in requests {
+                guard let trigger = request.trigger as? UNCalendarNotificationTrigger,
+                      let nextTriggerDate = trigger.nextTriggerDate() else {
+                    continue
+                }
+                
+                // If the next trigger date is more than 24 hours in the past
+                if nextTriggerDate.timeIntervalSince(now) < -24 * 60 * 60 {
+                    // Reschedule the notification
+                    let content = request.content.mutableCopy() as! UNMutableNotificationContent
+                    let newRequest = UNNotificationRequest(
+                        identifier: request.identifier,
+                        content: content,
+                        trigger: trigger
+                    )
+                    
+                    self.notificationCenter.add(newRequest) { error in
+                        if let error = error {
+                            DailyNotificationLogger.shared.log(
+                                .error,
+                                "Failed to reschedule notification: \(error.localizedDescription)"
+                            )
+                        } else {
+                            DailyNotificationLogger.shared.log(
+                                .info,
+                                "Successfully rescheduled notification: \(request.identifier)"
+                            )
+                        }
+                    }
+                }
+            }
+        }
+    }
+    
+    /// Schedules the next maintenance window
+    public func scheduleNextMaintenance() {
+        let trigger = UNTimeIntervalNotificationTrigger(
+            timeInterval: DailyNotificationConfig.SchedulingIntervals.normal,
+            repeats: true
+        )
+        
+        let content = UNMutableNotificationContent()
+        content.title = "Maintenance"
+        content.body = "Performing notification maintenance"
+        content.sound = nil
+        
+        let request = UNNotificationRequest(
+            identifier: "maintenance-window",
+            content: content,
+            trigger: trigger
+        )
+        
+        notificationCenter.add(request) { error in
+            if let error = error {
+                DailyNotificationLogger.shared.log(
+                    .error,
+                    "Failed to schedule maintenance window: \(error.localizedDescription)"
+                )
+            } else {
+                DailyNotificationLogger.shared.log(.info, "Maintenance window scheduled")
+            }
+        }
+    }
+}