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/downloads/adapters.py

@@ -10,6 +10,7 @@ Adapters are stateless singletons; get one with `resolve_adapter(source_kind, so
 Resolution works both before extraction (from source_kind / URL host) and after (from the yt-dlp
 `extractor_key` in the info dict), so a non-YouTube "url" job still lands on the right adapter.
 """
+
 from urllib.parse import urlparse
 
 from app.config import settings
@@ -140,8 +141,10 @@ def resolve_adapter(
     def host_is(*domains: str) -> bool:
         return any(_host_is(h, *domains) for h in hosts)
 
-    if source_kind == "youtube" or "youtube" in extractor or host_is(
-        "youtube.com", "youtu.be", "youtube-nocookie.com"
+    if (
+        source_kind == "youtube"
+        or "youtube" in extractor
+        or host_is("youtube.com", "youtu.be", "youtube-nocookie.com")
     ):
         return _YOUTUBE
     if "facebook" in extractor or host_is("facebook.com", "fb.watch"):