Fix 'Too many arguments': use **_kwargs in duration fns for extra params

Gradio introspects the duration callable's signature to determine the
expected input count for @spaces.GPU endpoints. Adding silent_video,
segments_json, total_dur_s as explicit params to _mmaudio_duration and
_hunyuan_duration caused Gradio to register 11/13 expected inputs vs the
9/10 actually wired in .click(inputs=[...]), triggering client-side
'Too many arguments' on every page load.

Fix: absorb the extra kwargs with **_kwargs in both duration functions
so Gradio sees only the 9/10 positional params matching the UI inputs.

app.py

@@ -1004,8 +1004,10 @@ def generate_taro(video_file, seed_val, cfg_scale, num_steps, mode,
 
 def _mmaudio_duration(video_file, prompt, negative_prompt, seed_val,
                       cfg_strength, num_steps, crossfade_s, crossfade_db, num_samples,
-                      silent_video=None, segments_json=None):
-    """Pre-GPU callable — must match _mmaudio_gpu_infer's input order exactly."""
+                      **_kwargs):
+    """Pre-GPU callable — must match _mmaudio_gpu_infer's input order exactly.
+    Extra kwargs (silent_video, segments_json) are absorbed by **_kwargs so the
+    duration fn signature stays in sync with the 9-input Gradio registration."""
     return _estimate_gpu_duration("mmaudio", int(num_samples), int(num_steps),
                                   video_file=video_file, crossfade_s=crossfade_s)
 
@@ -1151,8 +1153,9 @@ def generate_mmaudio(video_file, prompt, negative_prompt, seed_val,
 
 def _hunyuan_duration(video_file, prompt, negative_prompt, seed_val,
                       guidance_scale, num_steps, model_size, crossfade_s, crossfade_db,
-                      num_samples, silent_video=None, segments_json=None, total_dur_s=None):
-    """Pre-GPU callable — must match _hunyuan_gpu_infer's input order exactly."""
+                      num_samples, **_kwargs):
+    """Pre-GPU callable — must match _hunyuan_gpu_infer's input order exactly.
+    Extra kwargs (silent_video, segments_json, total_dur_s) absorbed by **_kwargs."""
     return _estimate_gpu_duration("hunyuan", int(num_samples), int(num_steps),
                                   video_file=video_file, crossfade_s=crossfade_s)