fix: latent upsampler dropdown silently reverted to auto after picking a file

sel.onchange only passed the filename, missing the "detail_upsampler" key
setSamplerInputNow(name, value) expects -- so it wrote sampler_inputs["<the
filename>"] = undefined instead of sampler_inputs.detail_upsampler, and the
next render recomputed the visible value from the untouched (still unset)
field and fell back to "auto". Matches the working sibling call one line
below (identity_projector).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

movie_editor/frontend/engine_settings.js

@@ -952,7 +952,7 @@
       if (c === cur) o.selected = true;
       sel.append(o);
     });
-    sel.onchange = () => S.setSamplerInputNow(sel.value);
+    sel.onchange = () => S.setSamplerInputNow("detail_upsampler", sel.value);
     // An upsampler has to take latents the same width as the model's, so on H3 the LTX
     // file is not a fallback and 'auto' deliberately will not fetch it. Promising a
     // download that cannot happen sends people to wait at the console for nothing.