refactor: Integrate message box into chat interface

Made the message input feel like part of the chat box:

Changes:
- Reduced chatbot height from 600px to 520px
- Removed labels from both chatbot and message box
- Set container=False on message box to reduce gaps
- Message box now feels integrated at bottom of chat

Before:
┌─────────────────┐
│ Chatbot │
│ (separate) │
└─────────────────┘
┌─────────────────┐
│ Message Box │
└─────────────────┘

After:
┌─────────────────┐
│ Chatbot │
│ │
├─────────────────┤
│ Message Box │ ← Feels unified
└─────────────────┘

This creates a WhatsApp-like unified chat interface.

Co-Authored-By: Claude <[email protected]>

app.py

@@ -273,24 +273,26 @@ with gr.Blocks() as demo:
 
     # Side-by-side layout: Chat on left, Visualization on right
     with gr.Row():
-        # Left column: Chat interface
+        # Left column: Chat interface (unified chat + message box)
         with gr.Column(scale=2):
-            # Use type="messages" for newer Gradio versions on HF Spaces
+            # Chatbot with reduced height to leave room for message box
             try:
-                chatbot = gr.Chatbot(type="messages", height=600)
+                chatbot = gr.Chatbot(type="messages", height=520, show_label=False)
             except TypeError:
                 # Fallback for older Gradio versions
-                chatbot = gr.Chatbot(height=600)
+                chatbot = gr.Chatbot(height=520, show_label=False)
 
+            # Message box directly below chatbot (no gap)
             msg = gr.MultimodalTextbox(
-                label="Message",
                 placeholder="Upload an X-ray image (JPG, PNG, DICOM) and ask a question...",
-                file_types=["image", ".dcm", ".dicom", ".DCM", ".DICOM"]
+                file_types=["image", ".dcm", ".dicom", ".DCM", ".DICOM"],
+                show_label=False,
+                container=False
             )
 
         # Right column: Visualization
         with gr.Column(scale=1):
-            viz_output = gr.Image(label="Visualization (Grounding/Segmentation)", height=600)
+            viz_output = gr.Image(label="Visualization", height=600)
 
     def respond(message, chat_history, mode_selection):
         # Convert mode selection to internal mode string