Replace custom JS fetch script with proper bricks-native pattern:
- actiontype: urlwidget, target: app.rl_asset_results, mode: replace
- method: POST in urlwidget options (required for form data)
- Remove duplicate id from dspy response widgets (id belongs to container only)
Remove submit_url + submited/urlwidget pattern (event.params is Response
object, not widget descriptor, causes silent failure).
Replace with submit event + actiontype:script that manually POSTs form
data via fetch() and renders response widget tree via bricks.widgetBuild.
