announce peer ID in servicedata to prevent duplicate connections (#613)

app/src/main/java/com/bitchat/android/mesh/BluetoothGattServerManager.kt

@@ -24,7 +24,8 @@ class BluetoothGattServerManager(
     private val connectionTracker: BluetoothConnectionTracker,
     private val permissionManager: BluetoothPermissionManager,
     private val powerManager: PowerManager,
-    private val delegate: BluetoothConnectionManagerDelegate?
+    private val delegate: BluetoothConnectionManagerDelegate?,
+    private val myPeerID: String
 ) {
     
     companion object {
@@ -372,13 +373,27 @@ class BluetoothGattServerManager(
             .setIncludeTxPowerLevel(false)
             .setIncludeDeviceName(false)
             .build()
+            
+        // Add stable identity (first 8 bytes of peerID) to Scan Response
+        // This allows scanners to deduplicate devices even if MAC address rotates
+        val peerIDBytes = try {
+            myPeerID.chunked(2).map { it.toInt(16).toByte() }.toByteArray().take(8).toByteArray()
+        } catch (e: Exception) {
+            ByteArray(0)
+        }
+        
+        val scanResponse = AdvertiseData.Builder()
+            .addServiceData(ParcelUuid(AppConstants.Mesh.Gatt.SERVICE_UUID), peerIDBytes)
+            .setIncludeTxPowerLevel(false)
+            .setIncludeDeviceName(false)
+            .build()
         
         advertiseCallback = object : AdvertiseCallback() {
             override fun onStartSuccess(settingsInEffect: AdvertiseSettings) {
                 val mode = try {
                     powerManager.getPowerInfo().split("Current Mode: ")[1].split("\n")[0]
                 } catch (_: Exception) { "unknown" }
-                Log.i(TAG, "Advertising started (power mode: $mode)")
+                Log.i(TAG, "Advertising started (power mode: $mode) with stable ID: ${peerIDBytes.joinToString("") { "%02x".format(it) }}")
             }
             
             override fun onStartFailure(errorCode: Int) {
@@ -387,7 +402,7 @@ class BluetoothGattServerManager(
         }
         
         try {
-            bleAdvertiser.startAdvertising(settings, data, advertiseCallback)
+            bleAdvertiser.startAdvertising(settings, data, scanResponse, advertiseCallback)
         } catch (se: SecurityException) {
             Log.e(TAG, "SecurityException starting advertising (missing permission?): ${se.message}")
         } catch (e: Exception) {