Cheap routing optimizations

- Don't relay back to sender or relayer
- Only send to connected device if recipientID matches one
- Don't relay our own ACK/read receipt

app/src/main/java/com/bitchat/android/model/RoutedPacket.kt

@@ -0,0 +1,13 @@
+package com.bitchat.android.model
+
+import com.bitchat.android.protocol.BitchatPacket
+
+/**
+ * Represents a routed packet with additional metadata
+ * Used for processing and routing packets in the mesh network
+ */
+data class RoutedPacket(
+    val packet: BitchatPacket,
+    val peerID: String? = null,           // Who sent it (parsed from packet.senderID)
+    val relayAddress: String? = null      // Address it came from (for avoiding loopback)
+)