template-builder-uilisted

# Sent Template Builder UI Design the interface around Sent's v3 `definition` contract. The UI may import Meta material, but its canonical saved and submitted model must never be Meta's `components[]` payload. ## Product model Use one draft object with: - optional `category` and `language`; - required `definition.body.multiChannel`; - optional complete body overrides for `sms`, `whatsapp`, and `rcs`; - optional `definition.header`, `footer`, `buttons`, `definitionVersion`, and `authenticationConfig`; - submission controls for `creation_source`, `submit_for_review`, and `sandbox`. Do not expose top-level create fields named `name`, `channels`, `body`, `header`, or `buttons`. If the product needs an internal display label, keep it outside the Sent create payload. ## Recommended editor sequence 1. Capture intent and category. 2. Write the `multiChannel` body. 3. Insert variables as structured entities. 4. Add optional per-channel overrides. 5. Add header, footer, and buttons where supported. 6. Review live previews and accessibility. 7. Validate locally and with `sandbox: true`. 8. Save a draft, then explicitly submit for provider review. Category should not block the first keystroke, but it must be visible before submission because it affects authentication rules and WhatsApp policy review. ## Variable UX Inserting a variable creates both: - a placeholder such as `{{0:variable}}`; and - a matching entity with `id`, `name`, `type`, and `props.sample`. Renumber atomic