chore(deploy): remove Dokploy, switch to native docker compose + Gitea Actions

- Remove Dokploy deploy jobs from GitHub CI workflow (test + build only)
- Add .gitea/workflows/ci.yml (Gitea Actions: lint, tests, docker build verify)
- Rewrite deploy.sh: set -euo pipefail, mandatory .env.<env>, --env-file,
  healthcheck on /api/health with log dump on failure
- Delete Dokploy-specific docs (3 files), update references in README,
  TODO.md, architecture.md, guides, dev plan
- Remove DOKPLOY_* env vars from proto/.env.local

REQUIREMENTS-CATALOG.md

@@ -553,14 +553,13 @@
 **Részletek**:
 - Automated testing
 - Docker image build
-- Registry push
-- Dokploy deployment
+- Natív deploy docker compose-szal (`deploy.sh`)
 
 **Acceptance Criteria**:
 - [x] GitHub Actions működik
 - [x] Automated testing aktív
 - [x] Docker build működik
-- [x] Deployment pipeline működik
+- [x] Deployment pipeline működik (natív docker compose)
 
 ---