更新新增三个模块

backend/app.py

@@ -0,0 +1,38 @@
+"""
+卖相AI - Flask 后端
+按功能拆分为蓝图：认证(auth)、主页面(main)、管理员API(admin_api)、版本(version)
+"""
+import os
+import secrets
+from datetime import timedelta
+
+from flask import Flask
+from flask_cors import CORS
+
+from utils.db import init_db
+from blueprints.auth import auth
+from blueprints.main import main
+from blueprints.admin_api import admin_api
+from blueprints.version import version_bp
+
+BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+app = Flask(__name__, template_folder=BASE_DIR, static_folder=BASE_DIR)
+
+CORS(app)
+app.secret_key = os.environ.get('SECRET_KEY', secrets.token_hex(32))
+app.config['PERMANENT_SESSION_LIFETIME'] = timedelta(days=7)
+
+# 注册蓝图
+app.register_blueprint(auth)
+app.register_blueprint(main)
+app.register_blueprint(admin_api)
+app.register_blueprint(version_bp)
+
+
+def run_app(host='0.0.0.0', port=15124):
+    init_db()
+    app.run(host=host, port=port, threaded=True, use_reloader=False)
+
+
+if __name__ == '__main__':
+    run_app()