build(client): use locked uv environment in launcher and Docker

s2s-client/README.md

@@ -31,17 +31,24 @@ Build from the repository root so the container includes the documentation:
 docker build -f s2s-client/Dockerfile -t s2s-client .
 ```
 
-Run the backend regression tests from the repository root after installing
-`requirements.txt` in `.venv`:
+The Python project is contained in this directory: `pyproject.toml`, `uv.lock`,
+`.python-version`, `.venv`, quality tools, and tests. Use uv 0.12.5 and Python
+3.12 (uv can provision Python). From the repository root:
 
 ```bash
-.venv/bin/python -m unittest discover -s s2s-client/tests -v
+make -C s2s-client install
+make -C s2s-client check
 ```
 
 Tests isolate environment configuration, use HTTP fixtures for allocation and
 caller authentication, and start a loopback WebSocket service to verify audio
 frames, keepalive, and teardown. No deployed services or database are needed.
 
+See [backend development and compatibility](../docs/client/development.md) for
+formatting, typing, schema policy, optional Git hooks, and deployment checks.
+`uvicorn server:app --app-dir s2s-client` remains a supported entry point;
+the implementation now lives in `s2s_client/`.
+
 FastAPI's API explorer remains at `/docs`. Project documents are served as files below
 `/docs/client/`, `/docs/speech/`, `/docs/adr/`, `/docs/examples/`, and
 `/docs/proposals/`. The historical `/project/` and `/public/docs.html` URLs