fix: change size_mb from string 'Unknown' to integer 0 to fix format error

app.py

@@ -98,7 +98,7 @@ def list_repo_gguf_files(repo_id: str) -> Tuple[List[Dict[str, Any]], str]:
             
             # Estimate size (we'd need to fetch file info for exact size)
             # For now, use placeholder that will be updated when downloading
-            size_mb = "Unknown"
+            size_mb = 0
             
             # Try to extract parameter count from filename
             params = "Unknown"