Merge pull request 'fix: handle expected BLE disconnect after SaveConfig' (#3) from schwifty/fix-saveconfig-disconnect into main

The previous fix only caught the disconnect callback path. But CoreBluetooth
can also fire didWriteValueFor with an error when the beacon reboots mid-ATT
response. This was hitting fail() at the isNonFatalCommand check instead of
being treated as success.

Now handles both paths:
1. didDisconnectPeripheral with state=.writing at last command → succeed()
2. didWriteValueFor error for SaveConfig (last command) → succeed()

Also added detailed state/index logging to disconnect handler for diagnostics.

PayfritBeacon/BeaconProvisioner.swift

@@ -966,15 +966,22 @@ extension BeaconProvisioner: CBCentralManagerDelegate {
     }
 
     func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: Error?) {
-        DebugLog.shared.log("BLE: Disconnected from \(peripheral.name ?? "unknown")")
+        DebugLog.shared.log("BLE: Disconnected from \(peripheral.name ?? "unknown") | state=\(state) mode=\(operationMode) writeIdx=\(dxSmartWriteIndex) queueCount=\(dxSmartCommandQueue.count) error=\(error?.localizedDescription ?? "none")")
         if operationMode == .readingConfig {
             if state != .success && state != .idle {
                 finishRead()
             }
         } else if state != .success && state != .idle {
             if case .failed = state {
-                // Already failed
+                // Already failed — disconnect is just cleanup
+                DebugLog.shared.log("BLE: Disconnect after failure, ignoring")
+            } else if state == .writing && dxSmartCommandQueue.count > 0 && dxSmartWriteIndex >= dxSmartCommandQueue.count - 1 {
+                // SaveConfig (last command) was sent — beacon rebooted to apply config
+                // This is expected behavior, treat as success
+                DebugLog.shared.log("BLE: Disconnect after SaveConfig (idx=\(dxSmartWriteIndex)/\(dxSmartCommandQueue.count)) — treating as success")
+                succeed()
             } else {
+                DebugLog.shared.log("BLE: UNEXPECTED disconnect — state=\(state) writeIdx=\(dxSmartWriteIndex) queueCount=\(dxSmartCommandQueue.count)")
                 fail("Unexpected disconnect", code: .disconnected)
             }
         }
@@ -1101,14 +1108,21 @@ extension BeaconProvisioner: CBPeripheralDelegate {
                     // Device name (0x71) and Frame 1 commands (steps 1-6) may be rejected by some firmware
                     // Treat these as non-fatal: log and continue to next command
                     let isNonFatalCommand = dxSmartWriteIndex < 6  // First 6 commands are optional
-                    if isNonFatalCommand {
+                    let isSaveConfig = dxSmartWriteIndex >= dxSmartCommandQueue.count - 1
+                    if isSaveConfig {
+                        // SaveConfig (0x60) write "error" is expected — beacon reboots immediately
+                        // after processing the save, which kills the BLE connection before the
+                        // ATT write response can be delivered. This is success, not failure.
+                        DebugLog.shared.log("BLE: SaveConfig write error (beacon rebooted) — treating as success")
+                        succeed()
+                    } else if isNonFatalCommand {
                         DebugLog.shared.log("BLE: Non-fatal command failed at step \(dxSmartWriteIndex + 1), continuing...")
                         dxSmartWriteIndex += 1
                         DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) { [weak self] in
                             self?.dxSmartSendNextCommand()
                         }
                     } else {
-                        fail("Command write failed at step \(dxSmartWriteIndex + 1): \(error.localizedDescription)", code: .writeFailed)
+                        fail("Command write failed at step \(dxSmartWriteIndex + 1)/\(dxSmartCommandQueue.count): \(error.localizedDescription)", code: .writeFailed)
                     }
                 }
                 return