fix: also hide video download button via CSS as belt-and-suspenders

show_download_button=False handles it at the component level; the CSS rule
ensures it stays hidden even if Gradio re-renders the slot unexpectedly.

app.py

@@ -1521,6 +1521,13 @@ _SLOT_CSS = """
     min-width: 0 !important;
     max-width: 50% !important;
 }
+/* Hide the built-in download button on output video slots — downloads are
+   handled by the waveform panel links which always reflect the latest regen. */
+[id^="slot_vid_"] .download-icon,
+[id^="slot_vid_"] button[aria-label="Download"],
+[id^="slot_vid_"] a[download] {
+    display: none !important;
+}
 """
 
 _GLOBAL_JS = """