Initial scaffold: static site served by nginx on :8080

- public/index.html served via nginx.conf (port 8080)
- Dockerfile: nginx:1.27-alpine + HEALTHCHECK
- .gitea/workflows/flow.yml: build + push to Gitea registry, rolling deploy
- stack.yml: Swarm service wired to Traefik (host testwebsite.dev.serso.org)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

nginx.conf

@@ -0,0 +1,17 @@
+server {
+    listen 8080;
+    server_name _;
+
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location / {
+        try_files $uri $uri/ =404;
+    }
+
+    location = /healthz {
+        access_log off;
+        add_header Content-Type text/plain;
+        return 200 "ok\n";
+    }
+}