fix: slim provisioning — skip extra frame disables + full reconnect on FFE2 miss

Two key changes:

1. Remove frames 3-6 disable commands (was steps 16-23, 8 extra BLE writes).
   We only configure Frame 1 (device info) and Frame 2 (iBeacon), then save.
   Fewer writes = fewer chances for supervision timeout disconnects.

2. When FFE2 characteristic goes missing after a disconnect, do a full
   disconnect → reconnect → re-discover services → re-auth → resume cycle
   instead of trying to rediscover characteristics on the same (stale GATT)
   connection. CoreBluetooth returns cached results on the same connection,
   so FFE2 stays missing. Full reconnect forces a fresh GATT discovery.

Write sequence is now 16 steps (down from 24).

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

PayfritBeacon/BeaconProvisioner.swift

@@ -470,8 +470,8 @@ class BeaconProvisioner: NSObject, ObservableObject {
         dxSmartWriteConfig()
     }
 
-    /// Build the full command sequence and start writing
+    /// Build the command sequence and start writing
-    /// New 24-step write sequence for DX-Smart CP28:
+    /// Slim write sequence for DX-Smart CP28 (no extra frame overwrites):
     ///  1. DeviceName    0x71 [name bytes]       — service point name (max 20 ASCII chars)
     ///  2. Frame1_Select 0x11                    — select frame 1
     ///  3. Frame1_Type   0x61                    — enable as device info (broadcasts name)
@@ -487,8 +487,11 @@ class BeaconProvisioner: NSObject, ObservableObject {
     /// 13. AdvInterval   0x78 [advInterval]
     /// 14. TxPower       0x79 [txPower]
     /// 15. TriggerOff    0xA0
-    /// 16-23. Frames 3-6  select + 0xFF (disable each)
+    /// 16. SaveConfig    0x60                    — persist to flash
-    /// 24. SaveConfig    0x60                    — persist to flash
+    ///
+    /// NOTE: Frames 3-6 are intentionally left untouched. Disabling extra frames
+    /// caused additional BLE writes that increased disconnect risk. We only write
+    /// the two frames we care about (device info + iBeacon) and save.
     private func dxSmartWriteConfig() {
         guard let config = config else {
             fail("No config provided", code: .noConfig)
@@ -553,21 +556,9 @@ class BeaconProvisioner: NSObject, ObservableObject {
         // 15. TriggerOff (0xA0)
         dxSmartCommandQueue.append(buildDXPacket(cmd: .triggerOff, data: []))
 
-        // --- Frames 3-6: Disable each ---
+        // Frames 3-6 intentionally left untouched — fewer writes = fewer disconnects
-        // 16-17. Frame 3: select (0x13) + disable (0xFF)
-        dxSmartCommandQueue.append(buildDXPacket(cmd: .frameSelectSlot2, data: []))
-        dxSmartCommandQueue.append(buildDXPacket(cmd: .frameDisable, data: []))
-        // 18-19. Frame 4: select (0x14) + disable (0xFF)
-        dxSmartCommandQueue.append(buildDXPacket(cmd: .frameSelectSlot3, data: []))
-        dxSmartCommandQueue.append(buildDXPacket(cmd: .frameDisable, data: []))
-        // 20-21. Frame 5: select (0x15) + disable (0xFF)
-        dxSmartCommandQueue.append(buildDXPacket(cmd: .frameSelectSlot4, data: []))
-        dxSmartCommandQueue.append(buildDXPacket(cmd: .frameDisable, data: []))
-        // 22-23. Frame 6: select (0x16) + disable (0xFF)
-        dxSmartCommandQueue.append(buildDXPacket(cmd: .frameSelectSlot5, data: []))
-        dxSmartCommandQueue.append(buildDXPacket(cmd: .frameDisable, data: []))
 
-        // 24. SaveConfig (0x60) — persist to flash
+        // 16. SaveConfig (0x60) — persist to flash
         dxSmartCommandQueue.append(buildDXPacket(cmd: .saveConfig, data: []))
 
         DebugLog.shared.log("BLE: DX-Smart command queue built with \(dxSmartCommandQueue.count) commands")
@@ -590,23 +581,43 @@ class BeaconProvisioner: NSObject, ObservableObject {
         progress = "Writing config (\(current)/\(total))..."
 
         guard let commandChar = characteristics[BeaconProvisioner.DXSMART_COMMAND_CHAR] else {
-            // After disconnect+reconnect, characteristic discovery may return incomplete results.
+            // FFE2 missing — the GATT cache is stale after a disconnect. Rediscovering
-            // Re-discover characteristics instead of hard-failing.
+            // characteristics on the same connection doesn't work because CoreBluetooth
-            if charRediscoveryCount < BeaconProvisioner.MAX_CHAR_REDISCOVERY, let service = configService {
+            // returns cached (stale) results. We need a full disconnect → reconnect →
+            // re-discover services → re-discover characteristics cycle.
+            if charRediscoveryCount < BeaconProvisioner.MAX_CHAR_REDISCOVERY {
                 charRediscoveryCount += 1
-                DebugLog.shared.log("BLE: FFE2 missing — re-discovering characteristics (attempt \(charRediscoveryCount)/\(BeaconProvisioner.MAX_CHAR_REDISCOVERY))")
+                DebugLog.shared.log("BLE: FFE2 missing — triggering full disconnect/reconnect (attempt \(charRediscoveryCount)/\(BeaconProvisioner.MAX_CHAR_REDISCOVERY))")
-                progress = "Re-discovering characteristics..."
+                progress = "FFE2 missing, reconnecting..."
-                state = .discoveringServices
+
-                scheduleCharRediscoveryTimeout()
+                // Use the existing disconnect retry path — it handles reconnect + re-auth + resume
-                DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) { [weak self] in
+                resumeWriteAfterDisconnect = true
-                    self?.peripheral?.discoverCharacteristics([
+                dxSmartAuthenticated = false
-                        BeaconProvisioner.DXSMART_NOTIFY_CHAR,
+                dxSmartNotifySubscribed = false
-                        BeaconProvisioner.DXSMART_COMMAND_CHAR,
+                passwordIndex = 0
-                        BeaconProvisioner.DXSMART_PASSWORD_CHAR
+                characteristics.removeAll()
-                    ], for: service)
+                responseBuffer.removeAll()
+                awaitingCommandResponse = false
+                cancelResponseGateTimeout()
+                state = .connecting
+
+                // Disconnect — didDisconnectPeripheral won't re-enter because we set state = .connecting
+                // and handle reconnect manually here
+                if let peripheral = peripheral, peripheral.state == .connected {
+                    centralManager.cancelPeripheralConnection(peripheral)
+                }
+
+                DispatchQueue.main.asyncAfter(deadline: .now() + 2.0) { [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
+                    DebugLog.shared.log("BLE: Reconnecting after FFE2 miss...")
+                    self.centralManager.connect(resolvedPeripheral, options: nil)
                 }
             } else {
-                fail("DX-Smart command characteristic (FFE2) not found after \(charRediscoveryCount) rediscovery attempts", code: .serviceNotFound)
+                fail("DX-Smart command characteristic (FFE2) not found after \(charRediscoveryCount) reconnect attempts", code: .serviceNotFound)
             }
             return
         }
@@ -1227,6 +1238,12 @@ extension BeaconProvisioner: CBCentralManagerDelegate {
         if state == .success || state == .idle {
             return
         }
+
+        // Intentional disconnect for FFE2 reconnect — we're already handling reconnect
+        if state == .connecting && resumeWriteAfterDisconnect {
+            DebugLog.shared.log("BLE: Intentional disconnect for FFE2 reconnect, ignoring")
+            return
+        }
         if case .failed = state {
             DebugLog.shared.log("BLE: Disconnect after failure, ignoring")
             return