bug: devcontainers uses an old debian version with no non-EOL python header libs

### Describe the bug

The devcontainers config cannot be used for python development. `mcr.microsoft.com/devcontainers/rust:bullseye` is based on debian bullseye, which only has libpython*-dev up to v3.9, [which is EOL](https://devguide.python.org/versions/). Microsoft provides a rust devcontainer image for bookworm, but that isn't much better, only going up to 3.11. However, this may be workable because the python bindings use the abi3-py311 target. If so, the uv config needs to be updated to lock the python version used in the dev environment, as currently it installs the latest (3.14).

### Steps to Reproduce

- Create a fresh devcontainer
- `cd bindings/python`
- `just setup` (installs python 3.14)
- `uv run just test`: fails to generate type stubs due to missing header libraries

### Expected Behavior

The devcontainer should include all tools necessary for development.

### Additional Context

Changing the base image of the devcontainer could cause problems across many other regions of the monorepo and needs thorough testing.

### Are you willing to submit a PR to fix this bug?

- [ ] Yes, I would like to submit a PR.

Start with the devcontainer configuration and reproduce the failure from bindings/python using just setup followed by uv run just test. Check the Rust image and Python version used by the environment; done means a fresh devcontainer provides the required Python header libraries and the Python binding tests complete successfully without disrupting the monorepo.

Written by the indexing model from the issue text.