style: drop aliased cross-module import (I001) — use a local _CAMPAIGNS_API constant

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/app/services/download_backends.py

@@ -25,17 +25,17 @@ from pathlib import Path
 
 from .gallery_dl import DownloadResult, ErrorType
 from .patreon_ingester import PatreonIngester
-from .patreon_resolver import (
-    _CAMPAIGNS_URL as _CAMPAIGNS_API,
-    extract_vanity,
-    resolve_campaign_id_for_source,
-)
+from .patreon_resolver import extract_vanity, resolve_campaign_id_for_source
 
 # Platforms whose download + verify go through the native ingester rather than
 # gallery-dl. gallery-dl still serves every other platform (subscribestar,
 # hentaifoundry, discord, pixiv, deviantart) unchanged.
 NATIVE_INGESTER_PLATFORMS = frozenset({"patreon"})
 
+# Mirrors patreon_resolver._CAMPAIGNS_URL — surfaced in resolution-failure
+# messages so the operator sees the exact lookup endpoint that was hit.
+_CAMPAIGNS_API = "https://www.patreon.com/api/campaigns"
+
 
 def uses_native_ingester(platform: str) -> bool:
     """True when `platform` is served by the native ingester (not gallery-dl).