fix(web): center active filters and compact mobile cards

tools/seed_preview_db.py

@@ -484,6 +484,7 @@ def seed_preview(
 
         rows: list[tuple[str, int, dict[str, int], float]] = []
         inserted_first_seen = 0
+        expected_rows = 0
         for video in selected:
             aid = int(video["aid"])
             first_seen_ts = first_seen_map[aid]
@@ -500,6 +501,7 @@ def seed_preview(
             synthetic_days = max(0, (latest_day - snapshot_start).days)
             if synthetic_days <= 0:
                 continue
+            expected_rows += synthetic_days
             age_days = max(
                 0.0,
                 (latest_day - shanghai_datetime(int(video["pubdate"] or 0)).date()).days,
@@ -661,7 +663,7 @@ def seed_preview(
         "first_seen_updated": inserted_first_seen,
         "snapshots_inserted": len(rows) - failed,
         "snapshots_failed": failed,
-        "snapshots_missing": (len(selected) * days) - len(rows),
+        "snapshots_missing": expected_rows - len(rows),
         "up_stat_rows": up_rows,
         "preview_marker": "preview:seeded=1",
     }