feat (infra): Trae 完成 asset_helper_backend 微服务基础架构 V1 初始化

核心实现：搭建 Monorepo 架构，完成 shared 共享包、gateway、user-service 基础框架开发
技术落地：严格匹配指定技术栈版本，完成 Docker、gRPC、FastAPI、PostgreSQL、Redis 等配置，实现服务间基础连通
配套文件：生成 Makefile、环境变量模板、数据库 / 脚本初始化文件及启动验证文档
架构定位：仅搭建基础架构骨架，无任何业务逻辑、业务规则及业务相关字段，为后续业务开发提供支撑

asset_helper_backend/infra/nginx/nginx.conf

@@ -0,0 +1,49 @@
+# Nginx 配置文件
+
+user nginx;
+worker_processes auto;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    include /etc/nginx/mime.types;
+    default_type application/octet-stream;
+
+    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
+                      '$status $body_bytes_sent "$http_referer" '
+                      '"$http_user_agent" "$http_x_forwarded_for"';
+
+    access_log /var/log/nginx/access.log main;
+    error_log /var/log/nginx/error.log warn;
+
+    sendfile on;
+    keepalive_timeout 65;
+
+    upstream gateway {
+        server gateway:8000;
+    }
+
+    server {
+        listen 80;
+        server_name localhost;
+
+        location / {
+            proxy_pass http://gateway;
+            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;
+        }
+
+        location /ws {
+            proxy_pass http://gateway;
+            proxy_http_version 1.1;
+            proxy_set_header Upgrade $http_upgrade;
+            proxy_set_header Connection "upgrade";
+            proxy_set_header Host $host;
+        }
+    }
+}