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/plex/_shared.py

@@ -31,11 +31,15 @@ def _content_libs(db: Session) -> tuple[list[int], list[int]]:
     """The BROWSABLE content libraries, partitioned into (movie_lib_ids, show_lib_ids) — the single
     source of the browse scope. Excludes HU overlay libraries (`overlay_of` set): those are never
     browsed on their own, they only lend their Hungarian metadata to the EN twin's rows (E5 S5)."""
-    libs = db.execute(
-        select(PlexLibrary).where(
-            PlexLibrary.enabled.is_(True), PlexLibrary.overlay_of.is_(None)
+    libs = (
+        db.execute(
+            select(PlexLibrary).where(
+                PlexLibrary.enabled.is_(True), PlexLibrary.overlay_of.is_(None)
+            )
         )
-    ).scalars().all()
+        .scalars()
+        .all()
+    )
     movie_lib_ids = [lb.id for lb in libs if lb.kind == "movie"]
     show_lib_ids = [lb.id for lb in libs if lb.kind == "show"]
     return movie_lib_ids, show_lib_ids