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 +2163,19 @@ export class BaileysStartupService extends ChannelStartupService {
               const remotesJidMap: Record<string, number> = {};
 
               for (const event of payload) {
+                // Group receipts arrive here instead of `messages.update`, with
+                // delivery carried by `receiptTimestamp` and read by `readTimestamp`
+                // (Baileys sets exactly one of them per event). Only the latter was
+                // consumed, so group delivery never reached the webhook.
+                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;
                 }