Client-side Protocol.gd expects rmp_serde::to_vec_named() (maps with string keys), but LocalBridge was using to_vec() (compact positional arrays). Fix send_snapshot and update all test serialization calls to match actual wire format. Also change EOF from Ok(vec![]) to BridgeError::Transport so bridge systems can detect disconnects. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>