v2.2.1: frontend closed-source + Docker one-click deploy

- Remove frontend source code (now in private repo)
- Add pre-built frontend/dist/ with Nginx serving
- Simplify docker-compose.yml (no Node.js build needed)
- Update README with docs index and Docker deploy guide
- Add admin order list and AI analysis stats tabs
- Add quick trade API routes
- Clean up redundant files (package-lock.json, yarn.lock, .iml)
- Add GitHub Actions workflow for frontend update automation

quantdinger_vue/deploy/nginx.conf

@@ -1,24 +0,0 @@
-server {
-    listen 80;
-    server_name  _;
-    # gzip config
-    gzip on;
-    gzip_min_length 1k;
-    gzip_comp_level 6;
-    gzip_types text/plain text/css text/javascript application/json application/javascript application/x-javascript application/xml;
-    gzip_vary on;
-    gzip_disable "MSIE [1-6]\.";
-
-    root /usr/share/nginx/html;
-    include /etc/nginx/mime.types;
-
-    location / {
-        try_files $uri $uri/ /index.html;
-    }
-
-#    location /api {
-#        proxy_pass https://preview.pro.antdv.com/api;
-#        proxy_set_header   X-Forwarded-Proto $scheme;
-#        proxy_set_header   X-Real-IP         $remote_addr;
-#    }
-}