feat(ios): implement createSchedule, updateSchedule, deleteSchedule, and enableSchedule methods

Implemented schedule CRUD methods using UserDefaults:

createSchedule():
- Creates new schedule with required kind field
- Auto-generates ID if not provided (kind_timestamp)
- Stores optional fields (cron, clockTime, jitterMs, backoffPolicy, stateJson)
- Adds to schedules array in UserDefaults
- Returns created schedule

updateSchedule():
- Updates existing schedule by ID
- Updates provided fields (enabled, cron, clockTime, jitterMs, backoffPolicy, stateJson, lastRunAt, nextRunAt)
- Returns updated schedule
- Rejects if schedule not found

deleteSchedule():
- Deletes schedule by ID from UserDefaults
- Removes from schedules array
- Rejects if schedule not found

enableSchedule():
- Enables or disables schedule by ID
- Updates enabled field in schedule
- Rejects if schedule not found

iOS Adaptations:
- Uses UserDefaults array instead of SQLite database
- In-memory array manipulation then persistence
- Maintains schedule structure matching Android

Progress: 44/52 methods implemented (85% complete)

ios/Plugin/DailyNotificationPlugin.swift

@@ -676,6 +676,188 @@ public class DailyNotificationPlugin: CAPPlugin {
         }
     }
     
+    /**
+     * Create schedule
+     * 
+     * Creates a new schedule and stores it in UserDefaults.
+     * 
+     * Equivalent to Android's createSchedule method.
+     */
+    @objc func createSchedule(_ call: CAPPluginCall) {
+        guard let scheduleJson = call.getObject("schedule") else {
+            call.reject("Schedule data is required")
+            return
+        }
+        
+        guard let kind = scheduleJson["kind"] as? String else {
+            call.reject("Schedule kind is required")
+            return
+        }
+        
+        // Generate ID if not provided
+        let id = scheduleJson["id"] as? String ?? "\(kind)_\(Int64(Date().timeIntervalSince1970 * 1000))"
+        
+        print("DNP-PLUGIN: Creating schedule: id=\(id), kind=\(kind)")
+        
+        // Build schedule dictionary
+        var schedule: [String: Any] = [
+            "id": id,
+            "kind": kind,
+            "enabled": scheduleJson["enabled"] as? Bool ?? true,
+            "createdAt": Int64(Date().timeIntervalSince1970 * 1000)
+        ]
+        
+        // Add optional fields
+        if let cron = scheduleJson["cron"] as? String {
+            schedule["cron"] = cron
+        }
+        if let clockTime = scheduleJson["clockTime"] as? String {
+            schedule["clockTime"] = clockTime
+        }
+        if let jitterMs = scheduleJson["jitterMs"] as? Int {
+            schedule["jitterMs"] = jitterMs
+        }
+        if let backoffPolicy = scheduleJson["backoffPolicy"] as? String {
+            schedule["backoffPolicy"] = backoffPolicy
+        }
+        if let stateJson = scheduleJson["stateJson"] as? String {
+            schedule["stateJson"] = stateJson
+        }
+        
+        // Add to schedules array
+        var schedules = getSchedulesFromUserDefaults()
+        schedules.append(schedule)
+        UserDefaults.standard.set(schedules, forKey: "DailyNotificationSchedules")
+        UserDefaults.standard.synchronize()
+        
+        print("DNP-PLUGIN: Schedule created successfully")
+        call.resolve(schedule)
+    }
+    
+    /**
+     * Update schedule
+     * 
+     * Updates an existing schedule in UserDefaults.
+     * 
+     * Equivalent to Android's updateSchedule method.
+     */
+    @objc func updateSchedule(_ call: CAPPluginCall) {
+        guard let id = call.getString("id") else {
+            call.reject("Schedule ID is required")
+            return
+        }
+        
+        guard let updates = call.getObject("updates") else {
+            call.reject("Updates are required")
+            return
+        }
+        
+        print("DNP-PLUGIN: Updating schedule: id=\(id)")
+        
+        var schedules = getSchedulesFromUserDefaults()
+        guard let index = schedules.firstIndex(where: { ($0["id"] as? String) == id }) else {
+            call.reject("Schedule not found: \(id)")
+            return
+        }
+        
+        // Update schedule fields
+        var schedule = schedules[index]
+        
+        if let enabled = updates["enabled"] as? Bool {
+            schedule["enabled"] = enabled
+        }
+        if let cron = updates["cron"] as? String {
+            schedule["cron"] = cron
+        }
+        if let clockTime = updates["clockTime"] as? String {
+            schedule["clockTime"] = clockTime
+        }
+        if let jitterMs = updates["jitterMs"] as? Int {
+            schedule["jitterMs"] = jitterMs
+        }
+        if let backoffPolicy = updates["backoffPolicy"] as? String {
+            schedule["backoffPolicy"] = backoffPolicy
+        }
+        if let stateJson = updates["stateJson"] as? String {
+            schedule["stateJson"] = stateJson
+        }
+        if let lastRunAt = updates["lastRunAt"] as? Int64 {
+            schedule["lastRunAt"] = lastRunAt
+        }
+        if let nextRunAt = updates["nextRunAt"] as? Int64 {
+            schedule["nextRunAt"] = nextRunAt
+        }
+        
+        schedules[index] = schedule
+        UserDefaults.standard.set(schedules, forKey: "DailyNotificationSchedules")
+        UserDefaults.standard.synchronize()
+        
+        print("DNP-PLUGIN: Schedule updated successfully")
+        call.resolve(schedule)
+    }
+    
+    /**
+     * Delete schedule
+     * 
+     * Deletes a schedule from UserDefaults.
+     * 
+     * Equivalent to Android's deleteSchedule method.
+     */
+    @objc func deleteSchedule(_ call: CAPPluginCall) {
+        guard let id = call.getString("id") else {
+            call.reject("Schedule ID is required")
+            return
+        }
+        
+        print("DNP-PLUGIN: Deleting schedule: id=\(id)")
+        
+        var schedules = getSchedulesFromUserDefaults()
+        let initialCount = schedules.count
+        schedules.removeAll { ($0["id"] as? String) == id }
+        
+        if schedules.count == initialCount {
+            call.reject("Schedule not found: \(id)")
+            return
+        }
+        
+        UserDefaults.standard.set(schedules, forKey: "DailyNotificationSchedules")
+        UserDefaults.standard.synchronize()
+        
+        print("DNP-PLUGIN: Schedule deleted successfully")
+        call.resolve()
+    }
+    
+    /**
+     * Enable/disable schedule
+     * 
+     * Enables or disables a schedule.
+     * 
+     * Equivalent to Android's enableSchedule method.
+     */
+    @objc func enableSchedule(_ call: CAPPluginCall) {
+        guard let id = call.getString("id") else {
+            call.reject("Schedule ID is required")
+            return
+        }
+        
+        let enabled = call.getBool("enabled") ?? true
+        
+        print("DNP-PLUGIN: Setting schedule enabled: id=\(id), enabled=\(enabled)")
+        
+        var schedules = getSchedulesFromUserDefaults()
+        guard let index = schedules.firstIndex(where: { ($0["id"] as? String) == id }) else {
+            call.reject("Schedule not found: \(id)")
+            return
+        }
+        
+        schedules[index]["enabled"] = enabled
+        UserDefaults.standard.set(schedules, forKey: "DailyNotificationSchedules")
+        UserDefaults.standard.synchronize()
+        
+        print("DNP-PLUGIN: Schedule enabled status updated")
+        call.resolve()
+    }
+    
     // MARK: - Permission Methods
     
     /**