chore(deploy): 更新本地开发 docker-compose 使用 Java 后端

- docker-compose.yml: 替换 NestJS 后端为 Java (Spring Boot) + MySQL 8.0
  - 前端端口 3000:80，后端端口 8080:8080，MySQL 端口 3306:3306
- nginx.conf: proxy_pass 改为 http://backend:8080（Java 内部端口）

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

docker-compose.yml

@@ -1,28 +1,49 @@
 version: '3.8'
 
 services:
+  mysql:
+    image: mysql:8.0
+    container_name: kg-mysql
+    restart: unless-stopped
+    environment:
+      MYSQL_ROOT_PASSWORD: reading_platform_pwd
+      MYSQL_DATABASE: reading_platform
+    volumes:
+      - mysql_data:/var/lib/mysql
+    ports:
+      - "3306:3306"
+    healthcheck:
+      test: ["CMD", "mysqladmin", "ping", "-h", "localhost"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
   backend:
     build:
-      context: ./reading-platform-backend
-    container_name: kindergarten-backend
+      context: ./reading-platform-java
+    container_name: kg-backend
     restart: unless-stopped
     ports:
-      - "3001:3001"
+      - "8080:8080"
     environment:
-      - PORT=3001
-      - NODE_ENV=production
-      - DATABASE_URL=file:/app/prisma/dev.db
-      - JWT_SECRET=${JWT_SECRET:-change-this-secret}
-      - JWT_EXPIRES_IN=7d
-      - FRONTEND_URL=http://localhost:8080
-      - PRISMA_QUERY_ENGINE_LIBRARY=/app/node_modules/.prisma/client/libquery_engine-linux-musl-openssl-3.0.x.so.node
+      - SPRING_PROFILES_ACTIVE=prod
+      - JWT_SECRET=${JWT_SECRET:-reading-platform-jwt-secret-key-must-be-at-least-256-bits-long}
+    volumes:
+      - uploads_data:/app/uploads
+    depends_on:
+      mysql:
+        condition: service_healthy
 
   frontend:
     build:
       context: ./reading-platform-frontend
-    container_name: kindergarten-frontend
+    container_name: kg-frontend
     restart: unless-stopped
     ports:
-      - "8080:80"
+      - "3000:80"
     depends_on:
       - backend
+
+volumes:
+  mysql_data:
+  uploads_data:

reading-platform-frontend/nginx.conf

@@ -10,12 +10,12 @@ server {
 
     # 反向代理后端 API
     location /api/ {
-        proxy_pass http://backend:3001;
+        proxy_pass http://backend:8080;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
     }
 
     location /uploads/ {
-        proxy_pass http://backend:3001;
+        proxy_pass http://backend:8080;
     }
 }