Adds ruff (lint + format check) as a dev dependency and gate, applies its
fixes across the codebase (modernized typing, safer zip usage, line
length), and adds a Gitea Actions workflow that lints, tests, builds, and
publishes to the Gitea PyPI registry on v*.*.* tag pushes.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
