style: apply ruff format across backend + scripts (line-length 100)

Mechanical, whole-tree `ruff format` pass — no behaviour change. Recorded in
.git-blame-ignore-revs (next commit) so git blame skips it.

backend/app/routes/feed.py

@@ -228,9 +228,7 @@ def set_video_state(
         # off); otherwise drop it. The in-app player fires this alongside a progress
         # checkpoint that may DELETE the same row, so tolerate it vanishing under us.
         row = db.execute(
-            select(VideoState).where(
-                VideoState.user_id == user.id, VideoState.video_id == video_id
-            )
+            select(VideoState).where(VideoState.user_id == user.id, VideoState.video_id == video_id)
         ).scalar_one_or_none()
         if row is not None:
             if row.position_seconds:
@@ -276,9 +274,7 @@ def clear_video_state(
     watch position and watched_at), as if it had never been opened. Saved/playlist membership
     lives elsewhere and is untouched."""
     row = db.execute(
-        select(VideoState).where(
-            VideoState.user_id == user.id, VideoState.video_id == video_id
-        )
+        select(VideoState).where(VideoState.user_id == user.id, VideoState.video_id == video_id)
     ).scalar_one_or_none()
     if row is not None:
         db.delete(row)
@@ -321,9 +317,7 @@ def set_video_progress(
     keep = position >= PROGRESS_MIN_SECONDS and not near_end
 
     row = db.execute(
-        select(VideoState).where(
-            VideoState.user_id == user.id, VideoState.video_id == video_id
-        )
+        select(VideoState).where(VideoState.user_id == user.id, VideoState.video_id == video_id)
     ).scalar_one_or_none()
 
     if not keep:
@@ -385,7 +379,10 @@ def get_video_detail(
         raise HTTPException(status_code=404, detail="Unknown video")
 
     try:
-        with quota.attribute(user.id, quota.QuotaAction.VIDEOS_LOOKUP), YouTubeClient(db, user) as yt:
+        with (
+            quota.attribute(user.id, quota.QuotaAction.VIDEOS_LOOKUP),
+            YouTubeClient(db, user) as yt,
+        ):
             items = yt.get_videos([video_id])
     except YouTubeError as exc:
         raise HTTPException(status_code=422, detail=f"YouTube lookup failed: {exc}")