feat: 深色主题UI、错误分类、批量抓取、健康度筛选

- 修复 datetime 时区不一致导致所有API 500错误的问题
- Feeds/Dashboard 页面改为深色表格主题，高对比度文字
- 添加错误类型自动分类（URL失效/被拒绝/超时/DNS失败/SSL错误等12种）
- 新增"下次抓取时间"列，从APScheduler获取
- 新增健康度筛选下拉，修复分页后过滤失效的bug
- "全部抓取"改为同步并发执行，基于当前筛选条件获取所有匹配源
- 新增数据库自动迁移机制，处理增量列变更

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/routers/feeds.py

@@ -5,8 +5,8 @@ from pydantic import BaseModel, HttpUrl
 from sqlalchemy.orm import Session
 from database import get_db
 from models import Feed
-from rss_fetcher import discover_feed_url, fetch_and_store_feed
-from scheduler import add_feed_job, remove_feed_job
+from rss_fetcher import discover_feed_url, fetch_and_store_feed, fetch_all_feeds
+from scheduler import add_feed_job, remove_feed_job, get_feed_next_run
 
 router = APIRouter(prefix="/feeds", tags=["feeds"])
 
@@ -55,9 +55,10 @@ def list_feeds(
     category: Optional[str] = None,
     search: Optional[str] = None,
     is_active: Optional[bool] = None,
+    health_status: Optional[str] = None,
     db: Session = Depends(get_db),
 ):
-    """获取 RSS 源列表，支持分页、分类筛选、搜索"""
+    """获取 RSS 源列表，支持分页、分类筛选、搜索、健康度筛选"""
     query = db.query(Feed)
 
     if category:
@@ -70,10 +71,22 @@ def list_feeds(
         )
 
     total = query.count()
-    feeds = query.order_by(Feed.created_at.desc()).offset(skip).limit(limit).all()
+
+    # 健康度是计算字段，需要在 Python 中过滤
+    if health_status:
+        all_feeds = query.order_by(Feed.created_at.desc()).all()
+        matched = []
+        for feed in all_feeds:
+            if feed.health_status() == health_status:
+                matched.append(feed)
+        total = len(matched)
+        feeds = matched[skip:skip + limit]
+    else:
+        feeds = query.order_by(Feed.created_at.desc()).offset(skip).limit(limit).all()
 
     results = []
     for feed in feeds:
+        next_run = get_feed_next_run(feed.id)
         data = {
             "id": feed.id,
             "url": feed.url,
@@ -84,10 +97,13 @@ def list_feeds(
             "fetch_interval_minutes": feed.fetch_interval_minutes,
             "last_fetch_at": feed.last_fetch_at.isoformat() if feed.last_fetch_at else None,
             "last_fetch_status": feed.last_fetch_status,
+            "last_error": feed.last_error,
+            "error_type": feed.error_type,
             "success_count": feed.success_count,
             "fail_count": feed.fail_count,
             "article_count": feed.article_count,
             "health_status": feed.health_status(),
+            "next_fetch_time": next_run.isoformat() if next_run else None,
             "created_at": feed.created_at.isoformat(),
         }
         results.append(data)
@@ -210,6 +226,24 @@ def delete_feed(feed_id: int, db: Session = Depends(get_db)):
     return {"message": "RSS 源已删除"}
 
 
+class BatchFetchRequest(BaseModel):
+    feed_ids: List[int]
+
+
+@router.post("/batch-fetch")
+def batch_fetch(data: BatchFetchRequest):
+    """批量抓取（并发同步执行，等待结果返回）"""
+    results = fetch_all_feeds(data.feed_ids)
+    success = sum(1 for r in results if r.get("success"))
+    fail = len(results) - success
+    return {
+        "message": f"完成：{success} 个成功，{fail} 个失败",
+        "total": len(results),
+        "success": success,
+        "fail": fail,
+    }
+
+
 @router.post("/{feed_id}/fetch")
 def trigger_fetch(feed_id: int, db: Session = Depends(get_db)):
     """手动触发抓取"""