CC-2005: [grep] [Python] Use uv and upgrade to 3.14

[andy1li]

Note

Switches Python grep starter from Pipenv/Python 3.13 to uv/Python 3.14, updating run scripts, configs, Dockerfile, and docs.

• Environment/Build:
  • Upgrade buildpack to python-3.14 in codecrafters.yml; add .python-version set to 3.14.
  • Add pyproject.toml and uv.lock; remove Pipfile and Pipfile.lock.
  • Add dockerfiles/python-3.14.Dockerfile based on astral/uv, with uv sync and dependency file env.
• Execution:
  • Replace pipenv run python3 -m app.main with uv run --quiet -m app.main in .codecrafters/run.sh and your_program.sh across compiled_starters/python, solutions/python/01-cq2/code, and starter_templates/python/code.
• Docs/Config:
  • Update README.md to require uv locally.
  • Update starter_templates/python/config.yml required_executable to "uv".
  • Expand .gitignore with UV/PDM/JetBrains/Ruff/PyPI entries.

^{Written by Cursor Bugbot for commit 551f1c3. This will update automatically on new commits. Configure here.}

[linear]

CC-2005 [Python] Use uv and upgrade to 3.14