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/cli.py

@@ -24,7 +24,7 @@ def crawl(
     """手动抓取指定日期的 HuggingFace Daily Papers。"""
     from app.config import settings
     from app.database import SessionLocal, engine
-    from app.models import init_db as _init
+    from app.database import init_db as _init
     from app.services.crawler import crawl_daily
 
     target = date_str or date.today().isoformat()
@@ -60,7 +60,7 @@ def summarize(
     """手动触发 AI 总结。"""
     from app.config import settings
     from app.database import SessionLocal, engine
-    from app.models import init_db as _init
+    from app.database import init_db as _init
     from app.services.summarizer import summarize_batch, summarize_single
 
     import os
@@ -96,7 +96,7 @@ def init_db():
     """初始化数据库表。"""
     from app.config import settings
     from app.database import engine
-    from app.models import init_db as _init
+    from app.database import init_db as _init
 
     import os