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

tests/test_preview_seed.py

@@ -203,6 +203,9 @@ def test_seed_preview_end_to_end():
             assert conn.execute(
                 "SELECT 1 FROM up_blacklist WHERE mid=?", (FAKE_BLACKLIST_MID,)
             ).fetchone() is not None
+            assert conn.execute(
+                "SELECT 1 FROM kv WHERE k='task:last:snapshot'"
+            ).fetchone() is not None
             up_rows = conn.execute(
                 "SELECT stat_date, follower FROM up_stat WHERE mid=37754047 "
                 "ORDER BY stat_date"