fix: resolve 10 code review issues

High priority:
- Fix concurrent race condition for view_count/like_count (atomic update)
- Add route request ID tracking to prevent race conditions
- Filter get_joke by status=approved (no pending content leak)
- Add error feedback for like button

Performance:
- Optimize random joke query (avoid full table sort)
- Limit page_size max to 100 (DoS prevention)

Medium:
- Add localStorage quota error handling
- Handle empty AI response gracefully
- Fix generate content title extraction

Low:
- Add rejected_jokes to stats API
- Update dashboard to show rejected count

api/main.py.bak

@@ -0,0 +1,39 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.config import API_TITLE, API_VERSION
+from app.routers import jokes_router, categories_router, auth_router, admin_router, settings_router
+from app.database import Base, engine
+from app.models.setting import AiSetting  # 注册模型，确保 create_all 能看到
+
+# 创建新表（如果不存在）
+Base.metadata.create_all(bind=engine)
+
+# Create FastAPI application
+app = FastAPI(title=API_TITLE, version=API_VERSION)
+
+# Configure CORS
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Mount routers
+app.include_router(jokes_router, prefix="/api")
+app.include_router(categories_router, prefix="/api")
+app.include_router(auth_router, prefix="/api")
+app.include_router(admin_router, prefix="/api")
+app.include_router(settings_router, prefix="/api")
+
+
+@app.get("/")
+def root():
+    return {"message": "欢迎使用笑话大全 API"}
+
+
+@app.get("/health")
+def health_check():
+    return {"status": "healthy"}