docs: add Web Client section to README

README.md

@@ -255,6 +255,19 @@ All fields are optional.
 }
 ```
 
+
+## Web Client
+
+A companion web application ([Racecraft](https://codeberg.org/jhunnius/racecraft)) provides a browser-based interface for live telemetry, session management, and data analysis visualization. It connects to the REST API and renders shift point charts, track maps, and real-time gauges.
+
+To use with the web client, start the API on all interfaces:
+
+```bash
+RUSTY_TELEMETRY_API_HOST=0.0.0.0 cargo run --release
+```
+
+Then start the web client on the same machine — it proxies `/api/*` to `localhost:8080` automatically. Access from any machine on the LAN via the Vite dev server's network URL.
+
 ## Testing
 
 ```bash