List your organisation's WhatsApp groups on WHATSAPP_OFFICIAL channels (most recently active first), optionally filtered to one channel via ?channelId=. Paginate with limit (default 50, max 100) and offset; hasMore indicates another page exists. Deleted groups remain listed with deleted: true. Group chats on other channel types are not part of this API (they still appear in the Chats endpoints with chatType: "group").

Security:

• The organisationId in the URL must match the organisation your JWT was issued for — requests for a different organisation fail with 401.
• Requires CRM_ADMIN, ACCOUNT_OWNER, or CRM_BOT role; other roles receive 403.
• Groups are only supported on WHATSAPP_OFFICIAL channels whose number is an Official Business Account (OBA); ineligible numbers receive 422.