Fix: do not reject empty packets that arent message type (#510)

* do not reject empty packets that arent message type

* leave message with empty byte array

* clean up comments

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

@@ -949,12 +949,11 @@ class BluetoothMeshService(private val context: Context) {
      * Send leave announcement
      */
     private fun sendLeaveAnnouncement() {
-        val nickname = delegate?.getNickname() ?: myPeerID
         val packet = BitchatPacket(
             type = MessageType.LEAVE.value,
             ttl = MAX_TTL,
             senderID = myPeerID,
-            payload = nickname.toByteArray()
+            payload = byteArrayOf()
         )
         
         // Sign the packet before broadcasting

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

@@ -50,24 +50,11 @@ class SecurityManager(private val encryptionService: EncryptionService, private
             return false
         }
         
-        // Validate packet payload
-        if (packet.payload.isEmpty()) {
-            Log.d(TAG, "Dropping packet with empty payload")
-            return false
-        }
-        
         // Replay attack protection (same 5-minute window as iOS)
         val currentTime = System.currentTimeMillis()
-        val packetTime = packet.timestamp.toLong()
-        val timeDiff = kotlin.math.abs(currentTime - packetTime)
-        
-//        if (timeDiff > MESSAGE_TIMEOUT) {
-//            Log.d(TAG, "Dropping old packet from $peerID, time diff: ${timeDiff/1000}s")
-//            return false
-//        }
+        val messageType = MessageType.fromValue(packet.type)
 
         // Duplicate detection
-        val messageType = MessageType.fromValue(packet.type)
         val messageID = generateMessageID(packet, peerID)
         if (messageType != MessageType.ANNOUNCE) {
             if (processedMessages.contains(messageID)) {