feat: WebSocket client mode for remote DimOS connection

[jeff-hykin]

Problem

dimos-viewer in --connect mode can't send click or teleop events back to DimOS when LCM multicast is unavailable across machines.

Solution

Switched the WebSocket module from server (axum) to client (tokio-tungstenite) that connects to the Python RerunWebSocketServer. Replaced --ws-port with --ws-url for explicit URL control. Added automatic reconnection with buffer drain on reconnect to prevent stale velocity commands from being sent. Moved WS_EVENTS.md protocol doc to repo root.

Breaking Changes

--ws-port CLI flag replaced by --ws-url. If previously using --ws-port 3030, now use --ws-url ws://127.0.0.1:3030/ws.

How to Test

Requires the jeff/fix/rconnect branch of dimos for the server side.

# Terminal 1: start the Python websocket server
cd <path-to-dimos>
git checkout jeff/fix/rconnect
python -c "
from dimos.visualization.rerun.websocket_server import RerunWebSocketServer
import threading
server = RerunWebSocketServer(port=3030)
server.clicked_point.subscribe(lambda pt: print(f'[CLICK] {pt.x:.3f},{pt.y:.3f},{pt.z:.3f}'))
server.tele_cmd_vel.subscribe(lambda tw: print(f'[TWIST] {tw}'))
server.start()
threading.Event().wait()
"

# Terminal 2: build and run the viewer
pixi run build && pixi run viewer -- --ws-url ws://127.0.0.1:3030/ws

Click in the 3D viewport and use WASD keys — should see [CLICK] and [TWIST] in terminal 1.

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