fix(maintenance): drop dead status=="saved" scan

Watch later became a built-in playlist, so "saved" is no longer a VideoState
status — the scan matched nothing and under-counted users impacted by a video
removal. The playlist loop already covers Watch later, so impact is now correct.
Route the local _now through the shared utils.now_utc.

backend/app/sync/maintenance.py

@@ -20,18 +20,19 @@ Quota: phase 1 costs ~(flagged / 50) units, phase 2 ~(batch / 50). Both respect
 backfill reserve as the other jobs so interactive syncs never starve.
 """
 import logging
-from datetime import datetime, timedelta, timezone
+from datetime import timedelta
 
-from sqlalchemy import or_, select
+from sqlalchemy import select
 from sqlalchemy.orm import Session
 
 from app import progress, quota, sysconfig
 from app.config import settings
-from app.models import Playlist, PlaylistItem, Video, VideoState
+from app.models import Playlist, PlaylistItem, Video
 from app.notifications import create_notification
 from app.state import get_maintenance_batch
 from app.sync.runner import get_service_user
 from app.sync.videos import apply_video_details, parse_dt
+from app.utils import now_utc as _now
 from app.youtube.client import YouTubeClient
 
 log = logging.getLogger("siftlode.maintenance")
@@ -45,10 +46,6 @@ GRACE_DAYS_BY_REASON = {
 DEFAULT_GRACE_DAYS = settings.maintenance_grace_days
 
 
-def _now() -> datetime:
-    return datetime.now(timezone.utc)
-
-
 def _grace_days(reason: str | None) -> int:
     return GRACE_DAYS_BY_REASON.get(reason or "", DEFAULT_GRACE_DAYS)
 
@@ -91,14 +88,9 @@ def _collect_user_impact(db: Session, videos: list[Video]) -> dict[int, list[dic
     impact: dict[int, set[str]] = {}
     if not ids:
         return {}
-    # Saved (VideoState.status == "saved").
-    for user_id, video_id in db.execute(
-        select(VideoState.user_id, VideoState.video_id).where(
-            VideoState.video_id.in_(ids), VideoState.status == "saved"
-        )
-    ):
-        impact.setdefault(user_id, set()).add(video_id)
-    # In any of the user's playlists (covers watch-later, which is a playlist).
+    # Anyone who had it in a playlist — which now also covers "saved": Watch later became a
+    # built-in playlist, so "saved" is no longer a VideoState status (the old status=="saved"
+    # scan matched nothing and under-counted impacted users).
     for user_id, video_id in db.execute(
         select(Playlist.user_id, PlaylistItem.video_id)
         .join(PlaylistItem, PlaylistItem.playlist_id == Playlist.id)