refactor(fetch_github_stars): remove redundant early-return guard in build_graphql_query

The empty-parts check after the loop makes the upfront `if not repos: return ""` guard redundant.

Co-Authored-By: Claude <noreply@anthropic.com>

website/fetch_github_stars.py

@@ -46,8 +46,6 @@ def save_cache(cache: dict) -> None:
 
 def build_graphql_query(repos: list[str]) -> str:
     """Build a GraphQL query with aliases for up to 100 repos."""
-    if not repos:
-        return ""
     parts = []
     for i, repo in enumerate(repos):
         owner, name = repo.split("/", 1)