fix(tools): backfill fan counts in chronological order

tests/test_preview_seed.py

@@ -203,6 +203,13 @@ def test_seed_preview_end_to_end():
             assert conn.execute(
                 "SELECT 1 FROM up_blacklist WHERE mid=?", (FAKE_BLACKLIST_MID,)
             ).fetchone() is not None
+            up_rows = conn.execute(
+                "SELECT stat_date, follower FROM up_stat WHERE mid=37754047 "
+                "ORDER BY stat_date"
+            ).fetchall()
+            followers = [int(row["follower"]) for row in up_rows]
+            assert followers == sorted(followers), followers
+            assert len(followers) == 8
         finally:
             conn.close()