Fix ProjectService param and Gradio 6 Audio component

- Fix ProjectService: db -> database
- Remove show_download_button from gr.Audio (Gradio 6.x)

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

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

src/ui/components/audio_player.py

@@ -24,12 +24,11 @@ def create_audio_player(
     """
 
     with gr.Group():
-        # Audio player
+        # Audio player - Gradio 6.x removed show_download_button
         audio_output = gr.Audio(
             label=label,
             type="filepath",
             interactive=False,
-            show_download_button=show_download,
         )
 
         # Waveform visualization