feat: add Railway one-click deployment support

- Add Dockerfile.railway for all-in-one container
- Add railway.toml configuration
- Add railway/nginx.conf and supervisord.conf
- Update README with Deploy on Railway button
- Update Chinese README with deployment instructions

railway/nginx.conf

@@ -0,0 +1,52 @@
+# Railway Nginx Configuration
+# Frontend static files + API proxy to backend
+
+server {
+    listen 8080;
+    server_name _;
+
+    root /usr/share/nginx/html;
+    index index.html;
+
+    # Gzip compression
+    gzip on;
+    gzip_vary on;
+    gzip_min_length 1024;
+    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml+rss application/javascript application/json;
+
+    # Frontend routes (SPA)
+    location / {
+        try_files $uri $uri/ /index.html;
+
+        # Cache static assets
+        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
+            expires 1y;
+            add_header Cache-Control "public, immutable";
+        }
+    }
+
+    # Proxy API requests to backend (runs on 8081 internally)
+    location /api/ {
+        proxy_pass http://127.0.0.1:8081/api/;
+        proxy_http_version 1.1;
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection 'upgrade';
+        proxy_set_header Host $host;
+        proxy_cache_bypass $http_upgrade;
+        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;
+
+        # Timeout for long-running API calls (AI inference)
+        proxy_connect_timeout 300s;
+        proxy_send_timeout 300s;
+        proxy_read_timeout 300s;
+    }
+
+    # Health check endpoint
+    location /health {
+        return 200 "OK\n";
+        add_header Content-Type text/plain;
+        access_log off;
+    }
+}