feat(ios): add DFU logging via os.Logger

Implement LoggerDelegate to forward Nordic DFU library log messages to
the unified os.Logger system. Logs are visible in Xcode console and
Console.app, filterable by subsystem (community.capacitor.nordic-dfu).

Author: microbit-matt-hillsdon

ios/Plugin/Plugin.swift

@@ -2,14 +2,16 @@ import Capacitor
 import NordicDFU
 import CoreBluetooth
 import Foundation
+import os
 import UserNotifications
 
 @objc(NordicDfuPlugin)
-public class NordicDfuPlugin: CAPPlugin, CBCentralManagerDelegate, DFUServiceDelegate, DFUProgressDelegate, NotificationHandlerProtocol {
+public class NordicDfuPlugin: CAPPlugin, CBCentralManagerDelegate, DFUServiceDelegate, DFUProgressDelegate, LoggerDelegate, NotificationHandlerProtocol {
     public var dfuChangeEvent: String = "DFUStateChanged"
     var notificationRequestLookup = [String: JSObject]()
     private var manager: CBCentralManager?
     private var dfuStartTime: TimeInterval?
+    private let logger = Logger(subsystem: "community.capacitor.nordic-dfu", category: "DFU")
 
     override public func load() {
         manager = CBCentralManager(delegate: self, queue: nil)
@@ -325,6 +327,7 @@ public class NordicDfuPlugin: CAPPlugin, CBCentralManagerDelegate, DFUServiceDel
         let peripheral = peripherals[0]
         starter.delegate = self
         starter.progressDelegate = self
+        starter.logger = self
         _ = starter.start(target: peripheral)
 
         call.resolve()
@@ -365,4 +368,17 @@ public class NordicDfuPlugin: CAPPlugin, CBCentralManagerDelegate, DFUServiceDel
             call.resolve(["notifications": permission])
         }
     }
+
+    public func logWith(_ level: LogLevel, message: String) {
+        switch level {
+        case .debug, .verbose:
+            logger.debug("\(message, privacy: .public)")
+        case .info, .application:
+            logger.info("\(message, privacy: .public)")
+        case .warning:
+            logger.warning("\(message, privacy: .public)")
+        case .error:
+            logger.error("\(message, privacy: .public)")
+        }
+    }
 }