fix: auto-reconnect on disconnect during device info read instead of failing

The beacon sometimes drops BLE connection during the optional MAC address
query (0x30) after auth. Previously this failed with "Disconnected after
auth during device info read". Now we reconnect and skip the MAC read on
retry, going straight to config write. MAC is nice-to-have, not required.

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

PayfritBeacon/BeaconProvisioner.swift

@@ -157,6 +157,7 @@ class BeaconProvisioner: NSObject, ObservableObject {
     private var dxSmartWriteIndex = 0
     private var provisioningMacAddress: String?
     private var awaitingDeviceInfoForProvisioning = false
+    private var skipDeviceInfoRead = false  // set after disconnect during device info — skip MAC read on reconnect
     private var isTerminating = false  // guards against re-entrant disconnect handling
 
     // Read config mode
@@ -215,6 +216,7 @@ class BeaconProvisioner: NSObject, ObservableObject {
         self.dxSmartWriteIndex = 0
         self.provisioningMacAddress = nil
         self.awaitingDeviceInfoForProvisioning = false
+        self.skipDeviceInfoRead = false
         self.isTerminating = false
         self.connectionRetryCount = 0
         self.currentBeacon = beacon
@@ -298,6 +300,7 @@ class BeaconProvisioner: NSObject, ObservableObject {
         dxSmartWriteIndex = 0
         provisioningMacAddress = nil
         awaitingDeviceInfoForProvisioning = false
+        skipDeviceInfoRead = false
         isTerminating = false
         connectionRetryCount = 0
         currentBeacon = nil
@@ -406,6 +409,14 @@ class BeaconProvisioner: NSObject, ObservableObject {
 
     /// Read device info (MAC address) before writing config
     private func dxSmartReadDeviceInfoBeforeWrite() {
+        // If we previously disconnected during device info read, skip it entirely
+        if skipDeviceInfoRead {
+            DebugLog.shared.log("BLE: Skipping device info read (reconnect after previous disconnect)")
+            skipDeviceInfoRead = false
+            dxSmartWriteConfig()
+            return
+        }
+
         guard let commandChar = characteristics[BeaconProvisioner.DXSMART_COMMAND_CHAR] else {
             DebugLog.shared.log("BLE: FFE2 not found, proceeding without MAC")
             dxSmartWriteConfig()
@@ -1012,16 +1023,43 @@ extension BeaconProvisioner: CBCentralManagerDelegate {
             return
         }
 
-        // Disconnect during device info read (post-auth, pre-write) — beacon may have
+        // Disconnect during device info read (post-auth, pre-write) — beacon dropped
-        // dropped the connection during the MAC address query. We authenticated but
+        // connection during the optional MAC address query. Instead of failing, reconnect
-        // lost connection before writing config, so this is a failure — but a known
+        // and skip the device info step (MAC is nice-to-have, not required).
-        // one with a clear retry path, not an unexplained "Unexpected disconnect".
         if state == .authenticating && awaitingDeviceInfoForProvisioning && dxSmartAuthenticated {
-            DebugLog.shared.log("BLE: Disconnect during device info read (post-auth) — connection lost before config write, failing with retry prompt")
             awaitingDeviceInfoForProvisioning = false
-            // Connection lost — can't write config without it, fail with specific message
+            skipDeviceInfoRead = true  // on reconnect, go straight to config write
-            fail("Disconnected after auth during device info read — please retry", code: .disconnected)
+
-            return
+            if connectionRetryCount < BeaconProvisioner.MAX_CONNECTION_RETRIES {
+                connectionRetryCount += 1
+                let delay = Double(connectionRetryCount)
+                progress = "Reconnecting (skip MAC read)..."
+                DebugLog.shared.log("BLE: Disconnect during device info read — reconnecting (\(connectionRetryCount)/\(BeaconProvisioner.MAX_CONNECTION_RETRIES)), will skip MAC read")
+
+                // Reset BLE state for reconnect
+                dxSmartAuthenticated = false
+                dxSmartNotifySubscribed = false
+                dxSmartCommandQueue.removeAll()
+                dxSmartWriteIndex = 0
+                characteristics.removeAll()
+                responseBuffer.removeAll()
+                state = .connecting
+
+                DispatchQueue.main.asyncAfter(deadline: .now() + delay) { [weak self] in
+                    guard let self = self, let beacon = self.currentBeacon else { return }
+                    guard self.state == .connecting else { return }
+
+                    let resolvedPeripheral = self.resolvePeripheral(beacon)
+                    self.peripheral = resolvedPeripheral
+                    resolvedPeripheral.delegate = self
+                    self.centralManager.connect(resolvedPeripheral, options: nil)
+                }
+                return
+            } else {
+                DebugLog.shared.log("BLE: Disconnect during device info read — max retries exhausted")
+                fail("Disconnected while reading device information (retries exhausted)", code: .disconnected)
+                return
+            }
         }
 
         // All other disconnects are unexpected