Build 2602262159: restore jellyfin-first user source

backend/app/services/jellyfin_sync.py

@@ -24,6 +24,8 @@ async def sync_jellyfin_users() -> int:
     if not isinstance(users, list):
         return 0
     save_jellyfin_users_cache(users)
+    # Jellyfin is the canonical source for local user objects; Jellyseerr IDs are
+    # matched as enrichment when possible.
     jellyseerr_users = get_cached_jellyseerr_users()
     candidate_map = build_jellyseerr_candidate_map(jellyseerr_users or [])
     imported = 0