Introduce a GiteaOAuthValidator for JWT and userinfo validation and
fallbacks, add /oauth/token proxy, and thread per-user tokens through
the
request context and automation paths. Update config and .env.example for
OAuth-first mode, add OpenAPI, extensive unit/integration tests,
GitHub/Gitea CI workflows, docs, and lint/test enforcement (>=80% cov).
The builder stage installed dependencies to /root/.local but the final
stage switched to the 'aegis' user who couldn't access /root/.local.
Fixed by copying dependencies to /home/aegis/.local and updating PATH
to point to the correct location.
