test: añade verificación de key.participant en metadata de reaction

Co-authored-by: aider (openrouter/openai/gpt-5) <aider@aider.chat>

tests/unit/services/response-queue.reactions.test.ts

@@ -79,4 +79,34 @@ describe('ResponseQueue - jobs de reacción (enqueue + sendOne)', () => {
     expect(captured.payload.reaction).toBe('🤖');
     expect(captured.payload.key).toEqual({ remoteJid: '123@g.us', fromMe: false, id: 'MSG-99' });
   });
+
+  it('sendOne incluye key.participant cuando viene en metadata (grupo, fromMe:false)', async () => {
+    const item = {
+      id: 43,
+      recipient: '120363401791776728@g.us',
+      message: '',
+      attempts: 0,
+      metadata: JSON.stringify({
+        kind: 'reaction',
+        emoji: '✅',
+        chatId: '120363401791776728@g.us',
+        messageId: 'MSG-100',
+        participant: '34650861805:32@s.whatsapp.net',
+        fromMe: false
+      }),
+    };
+
+    const res = await ResponseQueue.sendOne(item as any);
+    expect(res.ok).toBe(true);
+
+    expect(captured.url?.includes('/message/sendReaction/instance-1')).toBe(true);
+    expect(captured.payload).toBeDefined();
+    expect(captured.payload.reaction).toBe('✅');
+    expect(captured.payload.key).toEqual({
+      remoteJid: '120363401791776728@g.us',
+      fromMe: false,
+      id: 'MSG-100',
+      participant: '34650861805:32@s.whatsapp.net'
+    });
+  });
 });