Fix UI crash: replace hidden gr.Number with gr.Textbox for regen_seg inputs

gr.Number with visible=False triggers a Gradio 5 internal .split() error
on the number format string, breaking the UI layout. Use gr.Textbox('0')
instead — handlers already call int(seg_idx) so the cast is safe.

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

app.py

@@ -1763,7 +1763,7 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                     taro_samples    = gr.Slider(label="Generations", minimum=1, maximum=MAX_SLOTS, value=1, step=1)
                     taro_btn        = gr.Button("Generate", variant="primary")
                     # Hidden regen plumbing — do NOT remove (used as typed inputs for regen handlers)
-                    taro_regen_seg  = gr.Number(value=0, visible=False, elem_id="taro_regen_seg")
+                    taro_regen_seg  = gr.Textbox(value="0", visible=False, elem_id="taro_regen_seg")
                     taro_regen_state = gr.Textbox(value="", visible=False, elem_id="taro_regen_state")
 
                 with gr.Column():
@@ -1869,7 +1869,7 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                     mma_samples     = gr.Slider(label="Generations", minimum=1, maximum=MAX_SLOTS, value=1, step=1)
                     mma_btn         = gr.Button("Generate", variant="primary")
                     # Hidden regen plumbing
-                    mma_regen_seg   = gr.Number(value=0, visible=False, elem_id="mma_regen_seg")
+                    mma_regen_seg   = gr.Textbox(value="0", visible=False, elem_id="mma_regen_seg")
                     mma_regen_state = gr.Textbox(value="", visible=False, elem_id="mma_regen_state")
 
                 with gr.Column():
@@ -1959,7 +1959,7 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                     hf_samples      = gr.Slider(label="Generations", minimum=1, maximum=MAX_SLOTS, value=1, step=1)
                     hf_btn          = gr.Button("Generate", variant="primary")
                     # Hidden regen plumbing
-                    hf_regen_seg    = gr.Number(value=0, visible=False, elem_id="hf_regen_seg")
+                    hf_regen_seg    = gr.Textbox(value="0", visible=False, elem_id="hf_regen_seg")
                     hf_regen_state  = gr.Textbox(value="", visible=False, elem_id="hf_regen_state")
 
                 with gr.Column():