fix: enable background fetch on iOS

ios/App/App/AppDelegate.swift

@@ -1,5 +1,6 @@
 import UIKit
 import Capacitor
+import TSBackgroundFetch
 
 @UIApplicationMain
 class AppDelegate: UIResponder, UIApplicationDelegate {
@@ -8,9 +9,18 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
         // Override point for customization after application launch.
+        let fetchManager = TSBackgroundFetch.sharedInstance();
+        fetchManager?.didFinishLaunching();
         return true
     }
 
+    // [capacitor-background-fetch-plugin]
+    func application(_ application: UIApplication, performFetchWithCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
+        print("BackgroundFetchPlugin AppDelegate received fetch event");
+        let fetchManager = TSBackgroundFetch.sharedInstance();
+        fetchManager?.perform(completionHandler: completionHandler, applicationState: application.applicationState);
+    }
+
     func applicationWillResignActive(_ application: UIApplication) {
         // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
         // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.

ios/App/App/Info.plist

@@ -2,6 +2,10 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
+	<key>BGTaskSchedulerPermittedIdentifiers</key>
+	<array>
+		<string>com.transistorsoft.fetch</string>
+	</array>
 	<key>NSCalendarsUsageDescription</key>
 	<string>App uses calendar for schedule sync</string>
 	<key>CFBundleDevelopmentRegion</key>