部署：添加部署配置（nginx、systemd、Dockerfile），并改进会话列表与头像显示

deploy/nginx/chat.conf

@@ -0,0 +1,32 @@
+server {
+  listen 8443;
+  server_name your-domain.com;
+
+  root /var/www/chat/frontend;
+  index index.html;
+
+  location /api/ {
+    proxy_pass http://127.0.0.1:4000/;
+    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;
+    # For SSE/streaming
+    proxy_buffering off;
+    chunked_transfer_encoding off;
+  }
+
+  location / {
+    try_files $uri $uri/ /index.html;
+  }
+
+  # optional: serve assets with long cache
+  location ~* \.(?:css|js|jpg|jpeg|gif|png|svg|ico|woff2?)$ {
+    expires 30d;
+    access_log off;
+  }
+}