T01: Scaffold project and CI

[NagisaVon]

Summary

• scaffold the uv-managed git-paoding package with the full planned module layout
• add the Click git-paoding --version entry point and placeholder test
• configure Ruff, strict mypy, pytest markers, pre-commit, and commit uv.lock
• split GitHub CI into independent lint, typecheck, and Python 3.11-3.13 test jobs
• ignore .local/, .DS_Store, and common macOS metadata

Validation

• uv run git-paoding --version prints git-paoding, version 0.1.0
• Ruff lint and format checks pass
• strict mypy passes
• pytest passes on Python 3.11, 3.12, and 3.13
• intentional lint and type errors were verified to fail their respective gates
• source distribution and wheel build successfully

Scope

• release.yml remains out of scope for T16
• modules scheduled for T02 and later remain empty skeletons