Update to Gradio 6.x API

- Move css from gr.Blocks() to launch()
- Replace show_api with footer_links parameter
- Remove theme from Blocks (moved to launch in Gradio 6)

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

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

src/ui/app.py

@@ -190,10 +190,9 @@ class AudioCraftApp:
 
     def build(self) -> gr.Blocks:
         """Build the Gradio application."""
-        css = get_custom_css()
-
-        # Create Blocks - use minimal params for compatibility
-        with gr.Blocks(css=css) as app:
+        # In Gradio 6.x, theme/css moved to launch()
+        # Create Blocks with no styling params
+        with gr.Blocks() as app:
             # Header with VRAM monitor
             with gr.Row():
                 with gr.Column(scale=4):
@@ -307,11 +306,14 @@ class AudioCraftApp:
         if self.app is None:
             self.build()
 
+        # Gradio 6.x: theme/css go in launch()
+        css = get_custom_css()
+
         self.app.launch(
             server_name=server_name or self.settings.host,
             server_port=server_port or self.settings.gradio_port,
             share=share,
-            show_error=True,
+            css=css,
             **kwargs,
         )