[parvezk]

Description

Rewrites the run instructions in samples/client/lit/shell/README.md. A first-time user following them can hit two problems.

1. No API key step. The prerequisites list Node.js and uv but not Python or a Gemini API key, and there is no step that sets GEMINI_API_KEY. As a result, the agent exits at startup. The README now lists both prerequisites and shows how to either export the key or copy the agent's .env.example to .env, as the React and Angular sample READMEs already do.
2. Two different demo:restaurant scripts. In samples/client/lit, yarn demo:restaurant builds the renderer and runs the shell and the agent together, which is what the Quickstart uses. In samples/client/lit/shell, the README's directory, yarn demo:restaurant starts only the Python agent and blocks, and yarn dev has to run in a second terminal. The README listed both commands as bullets with no indication of this. It now documents both ways: Option A is the single command from samples/client/lit, and Option B is the two-terminal setup from samples/client/lit/shell.

The README also gives the UI's URL (http://localhost:5173).

Testing

• prettier --check samples/client/lit/shell/README.md passes.
• Checked the commands and relative links against samples/client/lit/package.json and samples/client/lit/shell/package.json.

Pre-launch Checklist

One time:

• I signed the CLA.
• I read the Contributors Guide.
• I read the Style Guide.
• I have built and run at least one sample.

For this PR:

• I have updated the relevant CHANGELOG.md file.
• I updated/added relevant documentation.
• My code changes (if any) have tests.
• If my branch is on a fork, I have verified that scripts/e2e_test.sh passes.

[gemini-code-assist]

Code Review

This pull request updates the README.md for the Lit shell sample to clarify prerequisites (including Python and Gemini API key setup) and provides two options for running the agent and dev server. The review feedback recommends adding comments to clarify that command blocks should be run from the repository root to avoid directory context confusion, and formatting the local URL as a clickable markdown link.