The act_runner service account doesn't have python in PATH. Delegating
to actions/setup-python@v5 which downloads/caches Python 3.11 reliably.
Also bump timeout-minutes 15 -> 20 to absorb first-run pip install.
Gitea Actions only scans .gitea/workflows/ and .github/workflows/. The
file under gitea/workflows/ (no leading dot) was never picked up. Other
files in gitea/workflows/ remain as templates copied into consumer repos.
- Create a new document `plans/implementation-plan-A-B.md` that consolidates the implementation plans for the Python rewrite (Phase A) and the migration to Linux Mint (Phase B).
- The document includes detailed sections such as executive summary, checklist, prerequisites, step-by-step activities, architectural hooks for future phases, risk matrix, and references.
- Ensure the plan is self-contained, adhering to specified structure and style guidelines, and does not introduce new technologies or modify existing files.