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>

deploy/nginx-hamkadr.ir.conf

@@ -0,0 +1,25 @@
+# hamkadr.ir reverse-proxy vhost for the EXISTING nginx on the server.
+# Install:
+#   sudo cp deploy/nginx-hamkadr.ir.conf /etc/nginx/sites-available/hamkadr.ir
+#   sudo ln -s /etc/nginx/sites-available/hamkadr.ir /etc/nginx/sites-enabled/
+#   sudo nginx -t && sudo systemctl reload nginx
+#   sudo certbot --nginx -d hamkadr.ir -d www.hamkadr.ir   # adds the :443 server + HTTP→HTTPS redirect
+#
+# APP_PORT below MUST match APP_PORT in the Gitea ENV_FILE secret (default 8090).
+
+server {
+    listen 80;
+    listen [::]:80;
+    server_name hamkadr.ir www.hamkadr.ir;
+
+    # The app binds 127.0.0.1:8090 (docker-compose.prod.yml) — never exposed publicly.
+    location / {
+        proxy_pass http://127.0.0.1:8090;
+        proxy_http_version 1.1;
+        proxy_set_header Host              $host;
+        proxy_set_header X-Real-IP         $remote_addr;
+        proxy_set_header X-Forwarded-For   $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;   # app's ForwardedHeaders reads this → knows it's HTTPS
+        proxy_read_timeout 60s;
+    }
+}