Add Gitea CI/CD for hamkadr.ir (Nexus build + self-hosted compose deploy)

- .gitea/workflows/ci-cd.yml: dotnet build via mirror.soroushasadi.com; self-hosted deploy with pg_dump backup, rollback tag, scoped recreate, /healthz wait, prune
- Dockerfile (sdk/aspnet 10 via Nexus) + nuget.docker.config + .dockerignore
- docker-compose.prod.yml: app on 127.0.0.1:APP_PORT, Postgres internal-only + named volume
- deploy/nginx-hamkadr.ir.conf + DEPLOY.md (ports: 22/80/443 only; DB never exposed)
- Prod seeds reference data only (no demo listings); ForwardedHeaders for nginx TLS; /healthz endpoint

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitignore

@@ -12,6 +12,7 @@ artifacts/
 
 ## App
 appsettings.*.local.json
+.env
 
 ## OS
 Thumbs.db