fix(web): align trend ranges, next runs and preview task records

tests/test_web_queries.py

@@ -142,6 +142,10 @@ def test_video_detail_and_trend():
             assert trend["available"] is True
             assert len(trend["points"]) == 3
 
+            # 请求区间早于首次快照时，从首次快照开始，不制造空白历史
+            wide = q.video_trend(101, days=30)
+            assert wide["dates"] == list(DATES)
+
             # 删除中间一天，折线在缺失日期应为 None，而不是插值
             db.write(lambda conn: conn.execute(
                 "DELETE FROM snapshot WHERE aid=101 AND stat_date=?",
@@ -204,6 +208,8 @@ def test_fans_candidates_system_and_export():
             assert fans["delta_7d"] is None
             assert fans["delta_cum"] == 20
             assert fans["options"][0]["mid"] == 37754047
+            wide = q.fans(days=30)
+            assert wide["dates"] == list(DATES)
 
             candidates = q.candidates()
             assert candidates["total"] == 2
@@ -220,6 +226,8 @@ def test_fans_candidates_system_and_export():
             assert system["errors"] == []
             assert system["preview"] is False
             assert system["next_runs"]["snapshot"] > 0
+            assert system["next_runs"]["folder_sync"] > FIXED_NOW
+            assert system["next_runs"]["discover"] > FIXED_NOW
 
             exported = q.export_videos(sort="view")
             assert exported["total"] == 3