Fix regen: replace gr.State with gr.Textbox(visible=False) for regen plumbing

gr.State stores values server-side and ignores data passed via queue/join API.
gr.Textbox(visible=False) is client-side and correctly receives seg_idx and
state_json from the JS direct queue API call.

app.py

@@ -1772,9 +1772,11 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                     (taro_slot_grps, taro_slot_vids,
                      taro_slot_waves) = _make_output_slots("taro")
 
-            # Hidden regen plumbing — gr.State has zero DOM footprint
-            taro_regen_seg   = gr.State(value="0")
-            taro_regen_state = gr.State(value="")
+            # Hidden regen plumbing — gr.Textbox(visible=False) so JS can pass
+            # values directly via the queue/join data array (gr.State is server-side
+            # and ignores data array values; Textbox is client-side and accepts them).
+            taro_regen_seg   = gr.Textbox(value="0", visible=False)
+            taro_regen_state = gr.Textbox(value="", visible=False)
 
             for trigger in [taro_video, taro_steps, taro_cf_dur]:
                 trigger.change(
@@ -1879,9 +1881,10 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                     (mma_slot_grps, mma_slot_vids,
                      mma_slot_waves) = _make_output_slots("mma")
 
-            # Hidden regen plumbing — gr.State has zero DOM footprint
-            mma_regen_seg   = gr.State(value="0")
-            mma_regen_state = gr.State(value="")
+            # Hidden regen plumbing — gr.Textbox(visible=False) so JS can pass
+            # values directly via the queue/join data array.
+            mma_regen_seg   = gr.Textbox(value="0", visible=False)
+            mma_regen_state = gr.Textbox(value="", visible=False)
 
             mma_samples.change(
                 fn=_update_slot_visibility,
@@ -1970,9 +1973,10 @@ with gr.Blocks(title="Generate Audio for Video", css=_SLOT_CSS, js=_GLOBAL_JS) a
                     (hf_slot_grps, hf_slot_vids,
                      hf_slot_waves) = _make_output_slots("hf")
 
-            # Hidden regen plumbing — gr.State has zero DOM footprint
-            hf_regen_seg    = gr.State(value="0")
-            hf_regen_state  = gr.State(value="")
+            # Hidden regen plumbing — gr.Textbox(visible=False) so JS can pass
+            # values directly via the queue/join data array.
+            hf_regen_seg    = gr.Textbox(value="0", visible=False)
+            hf_regen_state  = gr.Textbox(value="", visible=False)
 
             hf_samples.change(
                 fn=_update_slot_visibility,