Added

New endpoint — Delete (archive) a brand

Added DELETE /brands/{brand_id} to soft-delete a brand by ID. This archives the brand and disables its related sourcing queries, trademarks, customer assets, and designated takedown assets — matching the existing UI behavior.

Requires brand.delete permission for user-scoped API keys. Returns 200 with the deleted brand ID on success, 404 if not found, or 403 if unauthorized.