feat: home growth auto(7→1) and hourly recent-video snapshot

- Add analytics.home_growth_days (auto|1|7); API growth_days=auto tries 7 then 1
- Homepage shows active window and growth-board link; clearer empty reason
- New snapshot_recent scheduler task (schedule.recent_snapshot_minutes/days)
- run_recent_videos refreshes new aids only; never touches completed/backup
- Full 00:01 job keeps ok=1 skip (covers hourly refresh within 1h); mutex with recent

config.example.json

@@ -74,7 +74,9 @@
   "schedule": {
     "discover_minutes": 60,
     "snapshot_at": "00:01",
-    "candidate_ttl_days": 7
+    "candidate_ttl_days": 7,
+    "recent_snapshot_minutes": 60,
+    "recent_video_days": 2
   },
   "discover": {
     "keywords": ["咻咻满"],
@@ -110,6 +112,7 @@
     "maturity_days": 2,
     "min_view_for_ranking": 2000,
     "video_shrink_minutes": 60,
-    "shrink_minutes": null
+    "shrink_minutes": null,
+    "home_growth_days": "auto"
   }
 }