fix: replace render=False xregen outputs with real rendered slot components

Gradio's postprocess_data looks up output component IDs in session state.
Components created with render=False are not registered there, causing
KeyError: 153 (or whichever block ID was assigned).

Replace _xr_vid_out / _xr_wave_out (both render=False) with
taro_slot_vids[0] / taro_slot_waves[0] as dummy sinks for all three
xregen_* event handlers. The JS _listenAndApply listener applies the
returned video/HTML directly to the correct slot's DOM elements and
ignores Gradio's output routing, so these slot-0 components are never
visibly affected.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -2463,8 +2463,14 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
     _xr_seg       = gr.Textbox(value="0",  render=False)
     _xr_state     = gr.Textbox(value="",   render=False)
     _xr_slot_id   = gr.Textbox(value="",   render=False)
-    _xr_vid_out   = gr.Video(render=False)
-    _xr_wave_out  = gr.HTML(render=False)
+    # Dummy outputs for xregen events: must be real rendered components so Gradio
+    # can look them up in session state during postprocess_data.  The JS listener
+    # (_listenAndApply) applies the returned video/HTML directly to the correct
+    # slot's DOM elements and ignores Gradio's own output routing, so these
+    # slot-0 components simply act as sinks — their displayed value is overwritten
+    # by the real JS update immediately after.
+    _xr_dummy_vid  = taro_slot_vids[0]
+    _xr_dummy_wave = taro_slot_waves[0]
 
     # TARO cross-model regen inputs: seg_idx, state_json, slot_id, seed, cfg, steps, mode, cf_dur, cf_db
     _xr_taro_seed  = gr.Textbox(value="-1",  render=False)
@@ -2478,7 +2484,7 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
         inputs=[_xr_seg, _xr_state, _xr_slot_id,
                 _xr_taro_seed, _xr_taro_cfg, _xr_taro_steps,
                 _xr_taro_mode, _xr_taro_cfd, _xr_taro_cfdb],
-        outputs=[_xr_vid_out, _xr_wave_out],
+        outputs=[_xr_dummy_vid, _xr_dummy_wave],
         api_name="xregen_taro",
     )
 
@@ -2495,7 +2501,7 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
         inputs=[_xr_seg, _xr_state, _xr_slot_id,
                 _xr_mma_prompt, _xr_mma_neg, _xr_mma_seed,
                 _xr_mma_cfg, _xr_mma_steps, _xr_mma_cfd, _xr_mma_cfdb],
-        outputs=[_xr_vid_out, _xr_wave_out],
+        outputs=[_xr_dummy_vid, _xr_dummy_wave],
         api_name="xregen_mmaudio",
     )
 
@@ -2514,7 +2520,7 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                 _xr_hf_prompt, _xr_hf_neg, _xr_hf_seed,
                 _xr_hf_guide, _xr_hf_steps, _xr_hf_size,
                 _xr_hf_cfd, _xr_hf_cfdb],
-        outputs=[_xr_vid_out, _xr_wave_out],
+        outputs=[_xr_dummy_vid, _xr_dummy_wave],
         api_name="xregen_hunyuan",
     )