feat(ios): implement getPowerState, requestBatteryOptimizationExemption, and setAdaptiveScheduling methods

Implemented power and scheduling utility methods:

getPowerState():
- Returns power state code (0=unknown, 1=unplugged, 2=charging, 3=full)
- Returns isOptimizationExempt (always false on iOS)
- Uses UIDevice battery monitoring

requestBatteryOptimizationExemption():
- No-op on iOS (battery optimization not applicable)
- Exists for API compatibility with Android
- Background App Refresh is user-controlled in Settings

setAdaptiveScheduling():
- Enables/disables adaptive scheduling
- Stores setting in UserDefaults
- Matches Android behavior

iOS Adaptations:
- Battery optimization not applicable (Background App Refresh is system setting)
- Power state derived from battery state
- Adaptive scheduling stored in UserDefaults

Progress: 24/52 methods implemented (46% complete)

ios/Plugin/DailyNotificationPlugin.swift

@@ -922,6 +922,96 @@ public class DailyNotificationPlugin: CAPPlugin {
         }
     }
     
+    /**
+     * Get power state
+     * 
+     * Returns power state information.
+     * 
+     * Equivalent to Android's getPowerState method.
+     */
+    @objc func getPowerState(_ call: CAPPluginCall) {
+        print("DNP-PLUGIN: Getting power state")
+        
+        // iOS doesn't have battery optimization like Android
+        // Background App Refresh is the closest equivalent, but we can't check it directly
+        let isOptimizationExempt = false
+        
+        // Get battery state for power state code
+        UIDevice.current.isBatteryMonitoringEnabled = true
+        let batteryState = UIDevice.current.batteryState
+        
+        // Map battery state to power state code (same as getBatteryStatus)
+        let powerState: Int
+        switch batteryState {
+        case .unknown:
+            powerState = 0
+        case .unplugged:
+            powerState = 1
+        case .charging:
+            powerState = 2
+        case .full:
+            powerState = 3
+        @unknown default:
+            powerState = 0
+        }
+        
+        let result: [String: Any] = [
+            "powerState": powerState,
+            "isOptimizationExempt": isOptimizationExempt
+        ]
+        
+        print("DNP-PLUGIN: Power state: \(powerState), optimizationExempt=\(isOptimizationExempt)")
+        
+        call.resolve(result)
+    }
+    
+    /**
+     * Request battery optimization exemption
+     * 
+     * On iOS, this is a no-op as iOS doesn't have battery optimization settings
+     * like Android. Background App Refresh is controlled by the user in Settings.
+     * 
+     * Equivalent to Android's requestBatteryOptimizationExemption method.
+     */
+    @objc func requestBatteryOptimizationExemption(_ call: CAPPluginCall) {
+        print("DNP-PLUGIN: Requesting battery optimization exemption (iOS: no-op)")
+        
+        // iOS doesn't have battery optimization exemption like Android
+        // Background App Refresh is a system setting that users control
+        // We can't programmatically request exemption on iOS
+        // This method exists for API compatibility but does nothing
+        
+        call.resolve()
+    }
+    
+    /**
+     * Set adaptive scheduling
+     * 
+     * Enables or disables adaptive scheduling features.
+     * 
+     * Equivalent to Android's setAdaptiveScheduling method.
+     */
+    @objc func setAdaptiveScheduling(_ call: CAPPluginCall) {
+        guard let options = call.options else {
+            call.reject("Options are required")
+            return
+        }
+        
+        guard let enabled = options["enabled"] as? Bool else {
+            call.reject("enabled boolean is required")
+            return
+        }
+        
+        print("DNP-PLUGIN: Setting adaptive scheduling: enabled=\(enabled)")
+        
+        // Store adaptive scheduling setting in UserDefaults
+        UserDefaults.standard.set(enabled, forKey: "DailyNotificationAdaptiveScheduling")
+        UserDefaults.standard.synchronize()
+        
+        print("DNP-PLUGIN: Adaptive scheduling set successfully")
+        call.resolve()
+    }
+    
     // MARK: - Private Implementation Methods
     
     private func setupBackgroundTasks() {