fix: harden message hook session/group context and add integration coverage (#9859) (thanks @Drickon)

src/infra/outbound/deliver.test.ts

@@ -627,6 +627,8 @@ describe("deliverOutboundPayloads", () => {
     const { sendWhatsApp } = await runChunkedWhatsAppDelivery({
       mirror: {
         sessionKey: "agent:main:main",
+        isGroup: true,
+        groupId: "whatsapp:group:123",
       },
     });
     expect(sendWhatsApp).toHaveBeenCalledTimes(2);
@@ -643,6 +645,8 @@ describe("deliverOutboundPayloads", () => {
         channelId: "whatsapp",
         conversationId: "+1555",
         messageId: "w2",
+        isGroup: true,
+        groupId: "whatsapp:group:123",
       }),
     );
     expect(internalHookMocks.triggerInternalHook).toHaveBeenCalledTimes(1);