fix(sandbox): keep python-slim base while enabling reliable claude runtime

[christian-taillon]

Why

This aims to restore reliable sandbox execution with minimal change and preserve maintainer intent around a Python-slim runtime.

Closes #8.

What changed

• Keep sandbox image on python:3.11-slim.
• Install required runtime dependencies for Claude execution (npm + @anthropic-ai/claude-code).
• Add uv for Python packaging workflows in the sandbox.
• Keep non-root execution with UID/GID 1000 and non-interactive Claude config.

Minimal-change intent

• No broad architecture rewrite.
• Keep existing sandbox wiring and env passthrough model.
• Focus on making current design reliable across common Linux container environments.

Notes

An alternative Node-first sandbox path is documented in Issue #8 comments (referencing commit 612356e) in case the project later wants a dedicated packaged runtime image.

[HackingDave]

Thanks for this post, I took the bits needed to incorporate this and will get these features added. Good stuff!