Live test page — submissions are real. This renders the actual
HubSpot form through the same HubL form tag production uses.
Submitting creates or updates a contact.
Arrive here from a calculator CTA so the query string carries the
calc_* values, then read the panel before submitting.
Rendered by HubSpot, filled by
snippets/redirect-prefill.html — the exact script the guide
tells you to paste onto the production landing page.
Change which form this is in the page editor: click the form, then
pick from the dropdown.