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/plex/paths.py

@@ -7,6 +7,7 @@ is admin-configured (sysconfig ``plex_path_map``) as newline/comma-separated ``p
 pairs; the longest matching Plex prefix wins. An empty map means the paths are identical on both
 sides (Plex and Siftlode see the same filesystem).
 """
+
 from pathlib import Path
 
 from sqlalchemy.orm import Session
@@ -33,7 +34,7 @@ def map_path(db: Session, plex_path: str) -> str:
     """Translate a Plex-side absolute path to the local mount path (no mapping = unchanged)."""
     for plex_prefix, local_prefix in parse_map(sysconfig.get_str(db, "plex_path_map")):
         if plex_path == plex_prefix or plex_path.startswith(plex_prefix.rstrip("/") + "/"):
-            rest = plex_path[len(plex_prefix):].lstrip("/")
+            rest = plex_path[len(plex_prefix) :].lstrip("/")
             return str(Path(local_prefix) / rest) if rest else local_prefix
     return plex_path