fix(baileys): expose delivery receipts for group messages

Baileys routes receipts for group messages to `message-receipt.update`
instead of `messages.update` (see `handleReceipt` in messages-recv.ts).
In that branch, delivery arrives as `receiptTimestamp` while read
arrives as `readTimestamp` — but only `readTimestamp` was being
consumed, and `sendDataWebhook` was never called.

The practical effect is that delivery confirmation for group messages
never reaches the webhook. Individual chats confirm normally
(SERVER_ACK, DELIVERY_ACK, READ); groups produce no event at all, even
though WhatsApp does send the receipt and Baileys does receive it — one
per participant.

Verified on 2.3.7 with `LOG_BAILEYS=debug`: a single group message
produced four `tag: "receipt"` stanzas, and zero webhook calls.

This emits MESSAGES_UPDATE using the same flat payload as the
individual-chat branch, so no new event type is needed and existing
consumers keep working — `participant` is already part of the status
schema. The existing `readTimestamp` handling is untouched.

Author: gersonkm

src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts

@@ -2163,6 +2163,24 @@ export class BaileysStartupService extends ChannelStartupService {
               const remotesJidMap: Record<string, number> = {};
 
               for (const event of payload) {
+                // Baileys routes receipts for GROUP messages to `message-receipt.update`
+                // instead of `messages.update` (see handleReceipt in messages-recv.ts).
+                // Delivery arrives here as `receiptTimestamp`, while only `readTimestamp`
+                // was being consumed below — so delivery confirmation for group messages
+                // never reached the webhook, and integrators had no way to observe it.
+                //
+                // Emitted as MESSAGES_UPDATE with the same flat payload used by the
+                // individual-chat branch, so no new event type is required and existing
+                // consumers keep working. `participant` is already part of the schema.
+                this.sendDataWebhook(Events.MESSAGES_UPDATE, {
+                  keyId: event.key.id,
+                  remoteJid: event.key.remoteJid,
+                  fromMe: event.key.fromMe,
+                  participant: event.receipt.userJid,
+                  status: typeof event.receipt.receiptTimestamp === 'number' ? 'DELIVERY_ACK' : 'READ',
+                  instanceId: this.instanceId,
+                });
+
                 if (typeof event.key.remoteJid === 'string' && typeof event.receipt.readTimestamp === 'number') {
                   remotesJidMap[event.key.remoteJid] = event.receipt.readTimestamp;
                 }