Restore development support and minimize migration diff

[bdice]

Summary

• Restore a Python 3.14 development container that installs uv, syncs the locked environment, and forwards the documentation server port.
• Replace the machine-specific localhost:8004 references with a conventional, configurable port 8000 default.
• Minimize the migration diff by restoring existing workflow formatting, comments, and copyright years wherever the underlying files were otherwise unchanged.

Why

This is a focused follow-up to rapidsai#807 so the Sphinx migration retains the repository's development-container workflow and avoids unrelated review noise.

Validation

• Built and initialized the development container successfully with Python 3.14.6.
• Ran make check inside the development container.
• Ran uv run pre-commit run --all-files inside the development container.