fix: Disable API documentation to avoid Gradio schema bug

The TypeError in Gradio's get_api_info() was caused by its JSON schema
parser encountering additionalProperties: True (boolean) in the schema
for complex types like SessionState. Setting show_api=False prevents
Gradio from generating API documentation entirely, avoiding the bug.

app.py

@@ -770,7 +770,7 @@ def get_welcome_message():
 
 def create_demo():
     """Create and configure the Gradio demo application."""
-    with gr.Blocks(title="Video Analyzer") as demo:
+    with gr.Blocks(title="Video Analyzer", show_api=False) as demo:
         # Per-session state for ChromaDB collection
         session_state = gr.State(value=None)