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_plex_sync_txn.py

@@ -2,6 +2,7 @@
 libraries already mirrored (committed per section), not roll the whole reconcile back. Uses the DB
 lane (`db` fixture) with a faked PlexClient — skipped without Postgres.
 """
+
 from sqlalchemy import select
 
 from app.plex import people, sync
@@ -25,9 +26,9 @@ class _FakePlex:
 
 def test_late_section_failure_keeps_earlier_sections(db, monkeypatch):
     monkeypatch.setattr(sync.sysconfig, "get_bool", lambda *a, **k: True)  # plex_enabled
-    monkeypatch.setattr(sync, "_enabled_section_keys", lambda db: None)     # all sections wanted
+    monkeypatch.setattr(sync, "_enabled_section_keys", lambda db: None)  # all sections wanted
     monkeypatch.setattr(sync, "PlexClient", lambda db: _FakePlex())
-    monkeypatch.setattr(sync, "_sync_movies", lambda *a, **k: None)         # skip the real Plex fetch
+    monkeypatch.setattr(sync, "_sync_movies", lambda *a, **k: None)  # skip the real Plex fetch
 
     # Section 1 completes and commits; section 2's collections step raises → its work rolls back.
     def collections(db, plex, lib, stats):
@@ -75,7 +76,9 @@ def test_enrich_people_batch_dedupes_shared_cast(db):
     fake = _FakeMetaPlex(
         {
             "m1": {"Role": [{"tag": shared, "role": "Self"}, {"tag": "Alice Unique"}]},
-            "m2": {"Role": [{"tag": shared, "role": "Self", "thumb": thumb}, {"tag": "Bob Unique"}]},
+            "m2": {
+                "Role": [{"tag": shared, "role": "Self", "thumb": thumb}, {"tag": "Bob Unique"}]
+            },
         }
     )