Fix Too many arguments: separate gr.Group visibility from generation outputs

In Gradio 5 SSR mode, including gr.Group updates in the same outputs list
as gr.Video/gr.HTML/gr.State causes argument count mismatches. Fix by:
- Removing gr.Group from btn.click() outputs (now: vids+waves+states = 24)
- Adding .then(fn=_update_slot_visibility) after click for group visibility
- Applies to all three tabs: TARO, MMAudio, HunyuanFoley

app.py

@@ -1363,10 +1363,11 @@ def _unpack_outputs(flat: list, n: int, tab_prefix: str) -> list:
     """Turn a flat _pad_outputs list into Gradio update lists.
 
     flat has MAX_SLOTS * 3 items: [vid0, aud0, meta0, vid1, aud1, meta1, ...]
-    Returns updates for: grps + vids + waveforms + seg_states
+    Returns updates for vids + waveforms + seg_states only (NOT grps).
+    Group visibility is handled separately via .then() to avoid Gradio 5 SSR
+    'Too many arguments' caused by mixing gr.Group updates with other outputs.
     """
     n = int(n)
-    grp_updates  = [gr.update(visible=(i < n)) for i in range(MAX_SLOTS)]
     vid_updates  = []
     wave_updates = []
     state_updates= []
@@ -1386,7 +1387,7 @@ def _unpack_outputs(flat: list, n: int, tab_prefix: str) -> list:
                 value="<p style='color:#888;font-size:12px'>Generate audio to see waveform.</p>"
             ))
             state_updates.append(None)
-    return grp_updates + vid_updates + wave_updates + state_updates
+    return vid_updates + wave_updates + state_updates
 
 
 def _on_video_upload_taro(video_file, num_steps, crossfade_s):
@@ -1553,12 +1554,18 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                         flat[i * 3 + 2] = meta
                 return _unpack_outputs(flat, n, "taro")
 
-            taro_btn.click(
+            # Split group visibility into a separate .then() to avoid Gradio 5 SSR
+            # "Too many arguments" caused by including gr.Group in mixed output lists.
+            (taro_btn.click(
                 fn=_run_taro,
                 inputs=[taro_video, taro_seed, taro_cfg, taro_steps, taro_mode,
                         taro_cf_dur, taro_cf_db, taro_samples],
-                outputs=taro_slot_grps + taro_slot_vids + taro_slot_waves + taro_slot_states,
-            )
+                outputs=taro_slot_vids + taro_slot_waves + taro_slot_states,
+            ).then(
+                fn=_update_slot_visibility,
+                inputs=[taro_samples],
+                outputs=taro_slot_grps,
+            ))
 
             # Per-slot regen trigger wiring for TARO
             for _i, _rtrig in enumerate(taro_slot_rtrigs):
@@ -1624,12 +1631,16 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                         flat[i * 3 + 2] = meta
                 return _unpack_outputs(flat, n, "mma")
 
-            mma_btn.click(
+            (mma_btn.click(
                 fn=_run_mmaudio,
                 inputs=[mma_video, mma_prompt, mma_neg, mma_seed,
                         mma_cfg, mma_steps, mma_cf_dur, mma_cf_db, mma_samples],
-                outputs=mma_slot_grps + mma_slot_vids + mma_slot_waves + mma_slot_states,
-            )
+                outputs=mma_slot_vids + mma_slot_waves + mma_slot_states,
+            ).then(
+                fn=_update_slot_visibility,
+                inputs=[mma_samples],
+                outputs=mma_slot_grps,
+            ))
 
             for _i, _rtrig in enumerate(mma_slot_rtrigs):
                 _slot_id = f"mma_{_i}"
@@ -1695,12 +1706,16 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                         flat[i * 3 + 2] = meta
                 return _unpack_outputs(flat, n, "hf")
 
-            hf_btn.click(
+            (hf_btn.click(
                 fn=_run_hunyuan,
                 inputs=[hf_video, hf_prompt, hf_neg, hf_seed,
                         hf_guidance, hf_steps, hf_size, hf_cf_dur, hf_cf_db, hf_samples],
-                outputs=hf_slot_grps + hf_slot_vids + hf_slot_waves + hf_slot_states,
-            )
+                outputs=hf_slot_vids + hf_slot_waves + hf_slot_states,
+            ).then(
+                fn=_update_slot_visibility,
+                inputs=[hf_samples],
+                outputs=hf_slot_grps,
+            ))
 
             for _i, _rtrig in enumerate(hf_slot_rtrigs):
                 _slot_id = f"hf_{_i}"