Add Docker setup: nginx frontend + backend compose

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nginx.conf

@@ -0,0 +1,31 @@
+server {
+    listen 80;
+    server_name _;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    gzip on;
+    gzip_types text/css application/javascript application/json image/svg+xml;
+    gzip_min_length 1024;
+
+    # index.html – never cache so SW updates are picked up immediately
+    location = /index.html {
+        add_header Cache-Control "no-cache, no-store, must-revalidate";
+    }
+
+    # Static assets – long-term cache (cache busted by SW version)
+    location ~* \.(css|js)$ {
+        add_header Cache-Control "public, max-age=31536000, immutable";
+    }
+
+    # Service worker – no cache so browser always gets the latest version
+    location = /sw.js {
+        add_header Cache-Control "no-cache, no-store, must-revalidate";
+        add_header Service-Worker-Allowed "/";
+    }
+
+    # SPA fallback
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+}