修复多个问题

backend/app/main.py

@@ -4,9 +4,9 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from app.config import settings
-from app.database import Base, engine, SessionLocal
-from app.models import HTMLFile
+from app.database import Base, SessionLocal, engine, ensure_database_schema
 from app.routers import html
+from app.routers.html import cleanup_expired_files
 
 logging.basicConfig(
     level=logging.INFO,
@@ -14,18 +14,19 @@ logging.basicConfig(
 )
 logger = logging.getLogger(__name__)
 
+settings.html_storage_dir.mkdir(parents=True, exist_ok=True)
 Base.metadata.create_all(bind=engine)
+ensure_database_schema()
 
-# 删除过期记录
-db = SessionLocal()
-try:
-    deleted_count = HTMLFile.delete_expired_records(db)
-    if deleted_count > 0:
-        logger.info(f"Deleted {deleted_count} expired HTML file records")
-finally:
-    db.close()
-
-app = FastAPI(title=settings.app_name)
+app = FastAPI(
+    title=settings.app_name,
+    version="2.0.0",
+    description=(
+        "Store agent-generated educational HTML pages and return a direct access URL. "
+        "The generated OpenAPI document can be imported directly into Tencent Cloud "
+        "Agent plugins."
+    ),
+)
 
 app.add_middleware(
     CORSMiddleware,
@@ -38,6 +39,20 @@ app.add_middleware(
 app.include_router(html.router, prefix=settings.api_prefix)
 
 
-@app.get("/")
+@app.on_event("startup")
+def cleanup_on_startup() -> None:
+    db = SessionLocal()
+    try:
+        deleted_count = cleanup_expired_files(db)
+        if deleted_count > 0:
+            logger.info("Deleted %s expired HTML files during startup", deleted_count)
+    finally:
+        db.close()
+
+
+@app.get("/", summary="Health check")
 def health_check() -> dict[str, str]:
-    return {"message": "HTML Generator API is running"}
+    return {
+        "message": "HTML Knowledge API is running",
+        "openapi_url": "/openapi.json",
+    }