Move js/head to launch() — Gradio 6 ignores them on Blocks

Gradio 6.0 relocated the js and head parameters from the gr.Blocks
constructor to launch(). They were silently dropped (UserWarning only),
so the force-dark-mode redirect never ran and light-mode visitors still
got washed-out theme tokens.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app.py

@@ -1439,11 +1439,7 @@ FORCE_DARK_HEAD = '<meta name="color-scheme" content="dark">'
 
 
 def build_app() -> gr.Blocks:
-    with gr.Blocks(
-        title="NV-Generate",
-        js=FORCE_DARK_JS,
-        head=FORCE_DARK_HEAD,
-    ) as app:
+    with gr.Blocks(title="NV-Generate") as app:
         hero_group, hero_buttons = render_hero()
         ct_group, ct_back = workspace_ct.build(spaces_gpu_ct)
         mr_group, mr_back = workspace_mr.build(spaces_gpu_mr)
@@ -1476,4 +1472,6 @@ if __name__ == "__main__":
         show_error=True,
         css=CSS,
         theme=gr.themes.Base(),
+        js=FORCE_DARK_JS,
+        head=FORCE_DARK_HEAD,
     )