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/tests/test_feed_keyset.py

@@ -11,6 +11,7 @@ NULLs in published_at / view_count / duration_seconds / title / subscriber_count
 exercised on both a first and a second key). (The malformed-cursor -> 400 path is covered by
 test_feed_cursor.py.)
 """
+
 from datetime import datetime, timezone
 
 import pytest
@@ -19,8 +20,19 @@ from app.models import Channel, Subscription, User, Video
 
 # Every sort feedquery.sort_keys defines except "relevance" (which needs a search query to rank).
 _SORTS = [
-    "newest", "oldest", "views", "views_asc", "duration_desc", "duration_asc",
-    "title", "title_desc", "subscribers", "subscribers_asc", "priority", "priority_asc", "shuffle",
+    "newest",
+    "oldest",
+    "views",
+    "views_asc",
+    "duration_desc",
+    "duration_asc",
+    "title",
+    "title_desc",
+    "subscribers",
+    "subscribers_asc",
+    "priority",
+    "priority_asc",
+    "shuffle",
 ]
 
 
@@ -30,38 +42,52 @@ def _dt(day: int) -> datetime:
 
 def _seed(db):
     # Two channels; one has a NULL subscriber_count (exercises the subscribers sort's nulls_last).
-    db.add_all([
-        Channel(id="UCa", title="Channel A", subscriber_count=1000),
-        Channel(id="UCb", title="Channel B", subscriber_count=None),
-    ])
+    db.add_all(
+        [
+            Channel(id="UCa", title="Channel A", subscriber_count=1000),
+            Channel(id="UCb", title="Channel B", subscriber_count=None),
+        ]
+    )
     user = User(email="keyset@example.com", email_verified=True)
     db.add(user)
     db.flush()
-    db.add_all([
-        Subscription(user_id=user.id, channel_id="UCa", priority=5, hidden=False),
-        Subscription(user_id=user.id, channel_id="UCb", priority=0, hidden=False),
-    ])
+    db.add_all(
+        [
+            Subscription(user_id=user.id, channel_id="UCa", priority=5, hidden=False),
+            Subscription(user_id=user.id, channel_id="UCb", priority=0, hidden=False),
+        ]
+    )
     # 7 normal/organic videos. Deliberate duplicates (published_at day 1 x2, day 2 x2 and day 3 x2,
     # view_count 100 x2, duration 60 x2 / 30 x2) and NULLs spread across the still-nullable sort columns
     # (view_count / duration_seconds / title / subscriber_count) to exercise nulls_last. published_at is
     # NOT NULL (migration 0068), so no NULL there — the duplicates keep the id tiebreaker load-bearing.
     rows = [
         # id       ch     published    views  dur   title
-        ("vid00", "UCa", _dt(1),      100,   60,   "alpha"),
-        ("vid01", "UCa", _dt(1),      100,   60,   "beta"),
-        ("vid02", "UCa", _dt(2),      None,  None, "gamma"),
-        ("vid03", "UCb", _dt(2),      50,    120,  None),
-        ("vid04", "UCb", _dt(3),      200,   30,   "delta"),
-        ("vid05", "UCb", _dt(3),      None,  30,   "epsilon"),
-        ("vid06", "UCa", _dt(28),     None,  None, "zeta"),
+        ("vid00", "UCa", _dt(1), 100, 60, "alpha"),
+        ("vid01", "UCa", _dt(1), 100, 60, "beta"),
+        ("vid02", "UCa", _dt(2), None, None, "gamma"),
+        ("vid03", "UCb", _dt(2), 50, 120, None),
+        ("vid04", "UCb", _dt(3), 200, 30, "delta"),
+        ("vid05", "UCb", _dt(3), None, 30, "epsilon"),
+        ("vid06", "UCa", _dt(28), None, None, "zeta"),
     ]
-    db.add_all([
-        Video(
-            id=vid, channel_id=ch, published_at=pub, view_count=views, duration_seconds=dur,
-            title=title, is_short=False, live_status="none", via_search=False, via_explore=False,
-        )
-        for vid, ch, pub, views, dur, title in rows
-    ])
+    db.add_all(
+        [
+            Video(
+                id=vid,
+                channel_id=ch,
+                published_at=pub,
+                view_count=views,
+                duration_seconds=dur,
+                title=title,
+                is_short=False,
+                live_status="none",
+                via_search=False,
+                via_explore=False,
+            )
+            for vid, ch, pub, views, dur, title in rows
+        ]
+    )
     db.commit()
     return user, [r[0] for r in rows]
 
@@ -91,7 +117,9 @@ def test_cursor_walk_matches_the_unpaged_order(db, as_user, sort):
     full = [it["id"] for it in client.get(f"/api/feed?sort={sort}&limit=50").json()["items"]]
     # Guard against a vacuous pass: if seeding ever stops surfacing the videos, `walked == full` would
     # be [] == [] for every sort and never exercise the cursor. All 7 rows must be present.
-    assert len(full) == len(ids), f"{sort}: seed did not surface all rows — the walk would be vacuous"
+    assert len(full) == len(ids), (
+        f"{sort}: seed did not surface all rows — the walk would be vacuous"
+    )
 
     # Walk it two at a time via the cursor and reassemble.
     walked: list[str] = []