Remove 'type: choice' and 'options:' from workflow_dispatch inputs,
replacing with 'type: string'. The Gitea Actions runner may not support
the 'choice' type with 'options' subfield, causing the entire workflow
to fail registration silently. The workflow already has runtime
validation (lines 40-44) that rejects invalid environment values, so
the 'choice' type was redundant.
- Replace single-branch push trigger with test + main + workflow_dispatch
- Add environment determination (test → PATCH bump, main/prod → MINOR bump)
- Add semver calculation with conditional patch/minor logic
- Add env validation (fails early on invalid env)
- Remove pa- prefix from git tags (use plain semver)
- Test builds fresh image; main/prod promotes test image to prod
- Match final architecture spec from Archie
- Add Dockerfile for portainer-automation (multi-stage build)
- Add standalone docker-compose.yaml for PA service
- Add application-prod.properties (prod Portainer :9443)
- Add application-ci.properties (CI test endpoints)
- Add .env.example with documented env vars for PA
- Add PORTAINER_STACK.md with deployment guide, env var tables, architecture diagram
- Add CI workflow (portainer_automation_build_push.yml) for image build/push
- Update root docker-compose.yaml to include PA service
