refactor(agent-to-agent): destructure payload in applyA2aMessageGate

Per review: destructure the approval payload once instead of repeating
`payload.x`, and narrow `platform_id` up front so it's used directly (drops the
separate `targetAgentGroupId` local).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: 2 people

src/modules/agent-to-agent/message-gate.ts

@@ -8,24 +8,24 @@ import type { ApprovalHandler } from '../approvals/index.js';
 import { performAgentRoute, type RoutableAgentMessage } from './agent-route.js';
 
 export const applyA2aMessageGate: ApprovalHandler = async ({ session, payload, notify }) => {
-  const targetAgentGroupId = typeof payload.platform_id === 'string' ? payload.platform_id : '';
-  if (!targetAgentGroupId) {
+  const { id, platform_id, content, in_reply_to } = payload;
+  if (typeof platform_id !== 'string' || !platform_id) {
     notify('Message approved but the target agent group was missing from the request.');
     log.warn('a2a_message_gate apply: missing target', { sessionId: session.id });
     return;
   }
 
   const msg: RoutableAgentMessage = {
-    id: typeof payload.id === 'string' ? payload.id : `a2a-gate-${Date.now()}`,
-    platform_id: targetAgentGroupId,
-    content: typeof payload.content === 'string' ? payload.content : '',
-    in_reply_to: typeof payload.in_reply_to === 'string' ? payload.in_reply_to : null,
+    id: typeof id === 'string' ? id : `a2a-gate-${Date.now()}`,
+    platform_id,
+    content: typeof content === 'string' ? content : '',
+    in_reply_to: typeof in_reply_to === 'string' ? in_reply_to : null,
   };
 
-  await performAgentRoute(msg, session, targetAgentGroupId);
+  await performAgentRoute(msg, session, platform_id);
   log.info('Held agent message delivered after approval', {
     from: session.agent_group_id,
-    to: targetAgentGroupId,
+    to: platform_id,
     msgId: msg.id,
   });
 };