fix: allow Gradio to serve /tmp files so waveform audio loads (403 fix)

Gradio 5 on HF Spaces blocks file serving from outside its own managed
temp dir by default. WAV files written to /tmp/tmpXXX/... returned 403
when the waveform iframe fetched them via /gradio_api/file=...

Fix: pass allowed_paths=["/tmp"] to demo.launch() so Gradio serves any
path under /tmp, resolving the 403 and unblocking the canvas waveform.

app.py

@@ -2304,4 +2304,4 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
     hf_video.change(fn=_sync,   inputs=[hf_video],   outputs=[taro_video, mma_video])
 
 print("[startup] app.py fully loaded — regen handlers registered, SSR disabled")
-demo.queue(max_size=10).launch(ssr_mode=False, height=900)
+demo.queue(max_size=10).launch(ssr_mode=False, height=900, allowed_paths=["/tmp"])