Generate declaration template HTML using AI (Claude).

The AI generates HTML body content using the V5 CSS design system and we return it as an editable DRAFT (design_json + html_content) — it is NOT saved. The frontend opens it in the editor; the user picks the mandatory Tipo de Documento and saves via the normal POST /declaration-templates (which enforces a valid tipo_doc). This mirrors the import-document flow and guarantees no NULL-tipo_doc template is ever persisted.

Body: example_text: str (required, min 10 chars) — description of what the user wants placeholders: list[str] (required, min 1) — placeholder keys to include id_modulo: int (required) — 5, 11, or 12 name: str (optional) — template name (defaults to "Declaração IA") trigger_action: str (optional) — trigger for auto-generation tipo_doc: int (optional) — document type ID, pre-fills the draft's metadata