feat: enhance UI, refactor services, improve templates and tests

- Replace image_extractor with pdf_image_extractor service
- Enhance pi_client with expanded API capabilities
- Improve summarizer service with additional features
- Update admin routes with more endpoints
- Add login page template
- Enhance detail page with comprehensive layout
- Improve search and trends pages
- Update base template with additional elements
- Refactor tests for better coverage
- Add validate_summary script
- Update project configuration and dependencies

app/main.py

@@ -6,6 +6,7 @@ from contextlib import asynccontextmanager
 
 from fastapi import FastAPI
 from fastapi.staticfiles import StaticFiles
+from starlette.middleware.sessions import SessionMiddleware
 
 from app.config import settings
 from app.database import engine, init_db
@@ -56,17 +57,17 @@ def create_app() -> FastAPI:
     init_db(engine)
     logger.info("Database initialized at %s", settings.db_path)
 
-    # 安全警告
-    if settings.ADMIN_TOKEN == "change-me":
-        logger.warning(
-            "⚠️  ADMIN_TOKEN is the default value 'change-me'. Please change it in .env!"
-        )
+    # Session 中间件
+    app.add_middleware(SessionMiddleware, secret_key=settings.SECRET_KEY)
 
-    if settings.APP_HOST not in ("127.0.0.1", "localhost", "::1"):
+    # 安全警告
+    if settings.SECRET_KEY == "change-me":
         logger.warning(
-            "⚠️  APP_HOST=%s is not localhost. "
-            "Ensure ADMIN_TOKEN is properly set and access is restricted.",
-            settings.APP_HOST,
+            "⚠️  SECRET_KEY is the default value 'change-me'. Please change it in .env!"
+        )
+    if not settings.ADMIN_PASSWORD:
+        logger.warning(
+            "⚠️  ADMIN_PASSWORD is empty. Please set it in .env!"
         )
 
     # 静态文件