feat: implement core notification functionality for iOS and Android - Add settings management, proper error handling, and platform-specific implementations

ios/Plugin/DailyNotificationError.swift

@@ -0,0 +1,50 @@
+/**
+ * DailyNotificationError.swift
+ * Daily Notification Plugin for Capacitor
+ *
+ * Defines error types and handling for the notification plugin
+ */
+
+import Foundation
+
+/// Represents possible errors that can occur within the DailyNotification plugin
+///
+/// These errors provide specific failure cases and associated messages for better
+/// error handling and debugging in the notification scheduling process.
+public enum DailyNotificationError: Error {
+    /// Thrown when required parameters are missing or invalid
+    case invalidParameters(String)
+    
+    /// Thrown when notification permissions have not been granted
+    case permissionDenied
+    
+    /// Thrown when notification scheduling fails
+    case schedulingFailed(String)
+    
+    /// Thrown when time format is invalid (should be HH:mm)
+    case invalidTimeFormat
+    
+    /// Thrown when provided timezone identifier is invalid
+    case invalidTimezone
+    
+    /// Thrown when priority value is not one of: high, default, low
+    case invalidPriority
+    
+    /// Human-readable error messages for each error case
+    public var message: String {
+        switch self {
+        case .invalidParameters(let detail):
+            return "Invalid parameters: \(detail)"
+        case .permissionDenied:
+            return "Notification permissions not granted"
+        case .schedulingFailed(let reason):
+            return "Failed to schedule notification: \(reason)"
+        case .invalidTimeFormat:
+            return "Invalid time format. Expected HH:mm"
+        case .invalidTimezone:
+            return "Invalid timezone identifier"
+        case .invalidPriority:
+            return "Invalid priority value. Expected 'high', 'default', or 'low'"
+        }
+    }
+}