Use head= for JS injection instead of js= parameter

Gradio js= wraps code in AsyncFunction which rejects function
declarations. head= injects raw script tags into head section.
Wrap app code in DOMContentLoaded listener.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app.py

@@ -274,7 +274,7 @@ CUSTOM_CSS = _CHAT_UI_CSS + """
 """
 
 CUSTOM_JS = _CHAT_UI_JS + """
-;(function() {
+;document.addEventListener('DOMContentLoaded', function() {
     var API_BASE = window.location.origin;
     var tokenInput = document.getElementById('token-input');
     var fileInput = document.getElementById('file-input');
@@ -452,12 +452,13 @@ CUSTOM_JS = _CHAT_UI_JS + """
             chatInput.placeholder = 'Ask a question about your documents...';
         });
     });
-})();
+});
 """
 
 
 def build_app() -> gr.Blocks:
-    with gr.Blocks(title="Document Explorer", css=CUSTOM_CSS, js=CUSTOM_JS) as demo:
+    custom_head = f"<script>{CUSTOM_JS}</script>"
+    with gr.Blocks(title="Document Explorer", css=CUSTOM_CSS, head=custom_head) as demo:
         gr.HTML(CUSTOM_HTML)
 
         # Hidden state for file upload workspace