Python quickstart CodeBox demo can appear to do nothing in clean env

[MarkovWangRR]

Summary

The Python quickstart codebox.py example can look like a silent no-op for first-time users in a clean environment.

Reproduction

Using the current quickstart snippet:

import asyncio
import boxlite

async def main():
    code = """
import requests
response = requests.get('https://api.github.com/zen')
print(response.text)
"""

    async with boxlite.CodeBox() as codebox:
        result = await codebox.run(code)
        print(result)

if __name__ == "__main__":
    asyncio.run(main())

In a fresh python:slim runtime, this often returns empty output.

Why it happens

• The snippet imports requests but does not install it first.
• In fresh environments, requests is commonly missing (ModuleNotFoundError).
• CodeBox.run() returns stdout only, so errors in stderr are not visible from print(result).

User impact

For newcomers following the official quickstart, this feels like a broken first-run experience (no output, no obvious error).

Proposed fix

Update quickstart snippet to install dependency explicitly before running code:

async with boxlite.CodeBox() as codebox:
    await codebox.install_package("requests")
    result = await codebox.run(code)
    print(result)

Optionally, document that run() returns stdout only and that stderr is available via exec() when debugging failures.