fix: remove gr.Group from outputs — fixes silent button click failure

Gradio 5.x has a known bug where output components inside gr.Group()
break API schema introspection, causing click handlers to silently
do nothing. This was previously fixed in commit ffef688 but was
reintroduced during the full rewrite.

Also removed visible=False from video/audio outputs — Gradio handles
empty state correctly without it.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app.py

@@ -532,28 +532,28 @@ with gr.Blocks(
         )
 
     # ── Result section ───────────────────────────────────────────────────────
-    with gr.Group():
-        gr.Markdown("### RESULT")
-        with gr.Row():
-            video_output = gr.Video(
-                label="Dubbed video",
-                visible=False,
-            )
-            audio_output = gr.Audio(
-                label="Dubbed audio",
-                visible=False,
-            )
-        with gr.Row():
-            srt_preview = gr.Textbox(
-                label="Subtitles (SRT)",
-                lines=10,
-                interactive=False,
-                show_copy_button=True,
-            )
-            srt_download = gr.File(
-                label="Download SRT",
-                file_types=[".srt"],
-            )
+    # NOTE: Do NOT wrap outputs in gr.Group() — Gradio 5.x has a bug where
+    # output components inside gr.Group break API schema introspection,
+    # causing click handlers to silently do nothing.
+    gr.Markdown("### RESULT")
+    with gr.Row():
+        video_output = gr.Video(
+            label="Dubbed video",
+        )
+        audio_output = gr.Audio(
+            label="Dubbed audio",
+        )
+    with gr.Row():
+        srt_preview = gr.Textbox(
+            label="Subtitles (SRT)",
+            lines=10,
+            interactive=False,
+            show_copy_button=True,
+        )
+        srt_download = gr.File(
+            label="Download SRT",
+            file_types=[".srt"],
+        )
 
     # ── Footer ───────────────────────────────────────────────────────────────
     gr.HTML("""