Optimize BLE mesh network for robustness and range (#314)

- Fixed relay probability calculation for 2-node networks (0% relay needed)
- Added protocol ACKs to prevent unnecessary retransmissions
- Implemented MessageState for enhanced duplicate detection
- Added exponential backoff for collision avoidance
- Fixed duplicate sends for bidirectional connections
- Resolved packet ID generation issues using immutable fields only
- Implemented smart rate limiting with progressive throttling
- Removed unnecessary debug logging and fixed build warnings
- Optimized message routing to prevent flooding in small networks

Co-authored-by: jack <jackjackbits@users.noreply.github.com>

bitchatTests/Mocks/MockBluetoothMeshService.swift

@@ -73,7 +73,8 @@ class MockBluetoothMeshService: BluetoothMeshService {
                 timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
                 payload: payload,
                 signature: nil,
-                ttl: 3
+                ttl: 3,
+                sequenceNumber: 1
             )
             
             sentMessages.append((message, packet))
@@ -111,7 +112,8 @@ class MockBluetoothMeshService: BluetoothMeshService {
                 timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
                 payload: payload,
                 signature: nil,
-                ttl: 3
+                ttl: 3,
+                sequenceNumber: 1
             )
             
             sentMessages.append((message, packet))