Adds a .agents/environment.yaml blueprint so that Devin can automatically set up the development environment for this repo.

The setup steps mirror the CI setup in .github/actions/setup/action.yml:

• Installs uv and pre-commit
• Installs base packages (setuptools, wheel)
• Installs dev dependencies from internal/requirements.txt (ruff, pytest, mypy, jupyter, etc.)
• Installs the modal client
• Sets up pre-commit hooks (ruff lint + format)

The maintenance block re-runs dependency installation to pick up any changes to internal/requirements.txt or new modal releases.

Type of Change

• Other (Changes to the codebase, but not to examples)

Human Review Checklist

• Verify the initialize steps align with .github/actions/setup/action.yml
• Confirm pre-commit install is appropriate given .pre-commit-config.yaml exists
• Consider whether uv should be assumed pre-installed rather than explicitly installed via pip install uv
• Consider whether a virtualenv (e.g. uv venv .venv) should be used instead of --system installs

Link to Devin Session
Requested by: Rahul Chalamala