feat(growth): same-day 1-day baselines for new videos

Let 1-day view growth use a zero baseline for videos published today, and the first successful sample for older videos ingested today, without mixing those into 7/30-day rankings.

tools/seed_preview_db.py

@@ -237,8 +237,8 @@ def _insert_snapshot(
         """
         INSERT OR REPLACE INTO snapshot(
           stat_date, aid, "view", "like", favorite, coin, share, reply,
-          danmaku, captured_at, ok, err, src
-        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 'preview')
+          danmaku, captured_at, ok, err, src, view_open, open_captured_at
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 'preview', ?, ?)
         """,
         (
             stat_date,
@@ -253,6 +253,8 @@ def _insert_snapshot(
             int(captured_at),
             1 if ok else 0,
             err,
+            values.get("view") if ok else None,
+            int(captured_at) if ok else None,
         ),
     )