fix: pass arguments to Python via sys.argv instead of heredoc interpolation

- Use `python3 <<HEREDOC - "$arg1" "$arg2"` pattern
- Avoids bash variable substitution issues in heredoc
- Fixes hanging issue where parse_yaml was silently failing

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

artifact_comfyui_download.sh

@@ -191,23 +191,26 @@ parse_yaml() {
     local yaml_file="$1"
     local category="$2"
 
-    python3 - <<EOPYAML
+    python3 <<EOPYAML - "$yaml_file" "$category"
 import yaml
 import sys
 
+yaml_file = sys.argv[1]
+category = sys.argv[2]
+
 try:
-    with open('${yaml_file}', 'r') as f:
+    with open(yaml_file, 'r') as f:
         config = yaml.safe_load(f)
 
-    if '${category}' == 'settings':
+    if category == 'settings':
         settings = config.get('settings', {})
         print(f"CACHE_DIR={settings.get('cache_dir', '/workspace/huggingface_cache')}")
         print(f"PARALLEL_DOWNLOADS={settings.get('parallel_downloads', 1)}")
-    elif '${category}' == 'categories':
+    elif category == 'categories':
         for cat_name in config.get('model_categories', {}).keys():
             print(cat_name)
-    elif '${category}' in config.get('model_categories', {}):
-        models = config['model_categories']['${category}']
+    elif category in config.get('model_categories', {}):
+        models = config['model_categories'][category]
         for model in models:
             repo_id = model.get('repo_id', '')
             description = model.get('description', '')