fix: resolve write ACK on didWriteValueFor instead of waiting for notification

Frame1_DevInfo (cmd 0x61) and potentially other commands don't send a
separate FFE1 notification after being written. The code was waiting for
didUpdateValueFor (notification) to resolve responseContinuation, but it
never came — causing a 5s timeout on every such command.

The .withResponse write type already guarantees the BLE stack confirmed
delivery. Now didWriteValueFor resolves responseContinuation on success,
so commands that don't trigger notifications still complete immediately.

If a notification also arrives later, responseContinuation is already nil
so it's harmlessly ignored.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

PayfritBeacon/Provisioners/DXSmartProvisioner.swift

@@ -448,10 +448,18 @@ extension DXSmartProvisioner: CBPeripheralDelegate {
             return
         }
 
-        // Handle write errors for command writes
-        if let error, let cont = responseContinuation {
+        // For command writes (FFE1/FFE2): the .withResponse write confirmation
+        // IS the ACK. Some commands (e.g. 0x61 Frame1_DevInfo) don't send a
+        // separate FFE1 notification, so we must resolve here on success too.
+        // If a notification also arrives later, responseContinuation will already
+        // be nil — harmless.
+        if let cont = responseContinuation {
             responseContinuation = nil
-            cont.resume(throwing: error)
+            if let error {
+                cont.resume(throwing: error)
+            } else {
+                cont.resume(returning: Data())
+            }
         }
     }
 }

PayfritBeacon/Services/BLEManager.swift

@@ -65,7 +65,7 @@ final class BLEManager: NSObject, ObservableObject {
             ])
 
             scanTimer = Timer.scheduledTimer(withTimeInterval: duration, repeats: false) { [weak self] _ in
-                Task { @MainActor in
+                DispatchQueue.main.async {
                     self?.stopScan()
                 }
             }
@@ -235,26 +235,27 @@ final class BLEManager: NSObject, ObservableObject {
 extension BLEManager: CBCentralManagerDelegate {
 
     nonisolated func centralManagerDidUpdateState(_ central: CBCentralManager) {
-        Task { @MainActor in
-            bluetoothState = central.state
+        let state = central.state
+        DispatchQueue.main.async { [weak self] in
+            self?.bluetoothState = state
         }
     }
 
     nonisolated func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
-        Task { @MainActor in
-            onPeripheralConnected?(peripheral)
+        DispatchQueue.main.async { [weak self] in
+            self?.onPeripheralConnected?(peripheral)
         }
     }
 
     nonisolated func centralManager(_ central: CBCentralManager, didFailToConnect peripheral: CBPeripheral, error: Error?) {
-        Task { @MainActor in
-            onPeripheralFailedToConnect?(peripheral, error)
+        DispatchQueue.main.async { [weak self] in
+            self?.onPeripheralFailedToConnect?(peripheral, error)
         }
     }
 
     nonisolated func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: Error?) {
-        Task { @MainActor in
-            onPeripheralDisconnected?(peripheral, error)
+        DispatchQueue.main.async { [weak self] in
+            self?.onPeripheralDisconnected?(peripheral, error)
         }
     }
 
@@ -264,13 +265,18 @@ extension BLEManager: CBCentralManagerDelegate {
         advertisementData: [String: Any],
         rssi RSSI: NSNumber
     ) {
-        Task { @MainActor in
-            let name = peripheral.name ?? advertisementData[CBAdvertisementDataLocalNameKey] as? String ?? ""
-            let serviceUUIDs = advertisementData[CBAdvertisementDataServiceUUIDsKey] as? [CBUUID]
-            let mfgData = advertisementData[CBAdvertisementDataManufacturerDataKey] as? Data
-            let isConnectable = advertisementData[CBAdvertisementDataIsConnectable] as? Bool ?? false
+        // Capture values in nonisolated context before hopping to main
+        let name = peripheral.name ?? advertisementData[CBAdvertisementDataLocalNameKey] as? String ?? ""
+        let serviceUUIDs = advertisementData[CBAdvertisementDataServiceUUIDsKey] as? [CBUUID]
+        let mfgData = advertisementData[CBAdvertisementDataManufacturerDataKey] as? Data
+        let isConnectable = advertisementData[CBAdvertisementDataIsConnectable] as? Bool ?? false
+        let peripheralId = peripheral.identifier
+        let rssiValue = RSSI.intValue
 
-            let type = detectBeaconType(name: name, serviceUUIDs: serviceUUIDs, manufacturerData: mfgData)
+        DispatchQueue.main.async { [weak self] in
+            guard let self else { return }
+
+            let type = self.detectBeaconType(name: name, serviceUUIDs: serviceUUIDs, manufacturerData: mfgData)
 
             // Match Android behavior (lines 164-169):
             // Include devices that have a recognized type, OR
@@ -278,31 +284,31 @@ extension BLEManager: CBCentralManagerDelegate {
             // are connectable with a name (potential configurable beacon)
             if type == .unknown {
                 let hasName = !name.isEmpty
-                let hasIBeaconData = mfgData.flatMap { parseIBeaconData($0) } != nil
+                let hasIBeaconData = mfgData.flatMap { self.parseIBeaconData($0) } != nil
                 if !hasIBeaconData && !(isConnectable && hasName) {
                     return
                 }
             }
 
-            if let idx = discoveredBeacons.firstIndex(where: { $0.id == peripheral.identifier }) {
+            if let idx = self.discoveredBeacons.firstIndex(where: { $0.id == peripheralId }) {
                 // Update existing
-                discoveredBeacons[idx].rssi = RSSI.intValue
-                discoveredBeacons[idx].lastSeen = Date()
+                self.discoveredBeacons[idx].rssi = rssiValue
+                self.discoveredBeacons[idx].lastSeen = Date()
             } else {
                 // New beacon
                 let beacon = DiscoveredBeacon(
-                    id: peripheral.identifier,
+                    id: peripheralId,
                     peripheral: peripheral,
                     name: name,
                     type: type,
-                    rssi: RSSI.intValue,
+                    rssi: rssiValue,
                     lastSeen: Date()
                 )
-                discoveredBeacons.append(beacon)
+                self.discoveredBeacons.append(beacon)
             }
 
             // Keep list sorted by RSSI (strongest/closest first)
-            discoveredBeacons.sort { $0.rssi > $1.rssi }
+            self.discoveredBeacons.sort { $0.rssi > $1.rssi }
         }
     }
 }

PayfritBeacon/Views/ScanView.swift

@@ -631,7 +631,7 @@ struct ScanView: View {
             // Monitor for unexpected disconnects during provisioning
             bleManager.onPeripheralDisconnected = { [weak provisionLog] peripheral, error in
                 if peripheral.identifier == beacon.peripheral.identifier {
-                    Task { @MainActor [weak self] in
+                    DispatchQueue.main.async { [weak self] in
                         let reason = error?.localizedDescription ?? "beacon timed out"
                         provisionLog?.log("disconnect", "Unexpected disconnect: \(reason)", isError: true)
                         guard let self = self else { return }