fix(external-agent): refresh editor online lease in registry touch

registry.touch() validated the editor and renewed store ownership but never
updated lastSeen, so an idle-but-polling editor dropped out of isConnected()
35s after registration. From there every MCP flow deadlocked: browser
bindings were rejected as disconnected while the stale registration still
blocked the offline fallback ("already has an active browser or offline
editor").

The regression guard added in #70 (broker-poll-refresh.verify.ts) actually
fails from its introducing commit for this reason; run-affected-verifies
maps no suite to these files, which is likely how it slipped through. This
one-line fix makes the existing guard pass and adds a direct-touch scenario
that covers bridge-route touches outside the long-poll wait loop.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: Lenouw

server/external-agent/broker-poll-refresh.verify.ts

@@ -5,6 +5,7 @@ import {
   nextEditorCall,
   registerEditor,
   resetExternalAgentBrokerForTest,
+  touchEditor,
 } from './broker.ts';
 
 const projectId = 'project-poll-refresh';
@@ -50,4 +51,29 @@ try {
   resetExternalAgentBrokerForTest();
 }
 
+// Direct-touch scenario: bridge routes touch the editor outside the long-poll
+// wait loop (poll entry, tool settle). A validated touch must refresh the
+// online lease too, or an idle editor drops out of isConnected() after
+// ONLINE_MS while its registration still blocks the offline fallback.
+resetExternalAgentBrokerForTest();
+mock.timers.enable({ apis: ['Date', 'setTimeout'] });
+try {
+  const registrationCapability = registerEditor(projectId, editorId, revision, tools, undefined, null);
+  mock.timers.setTime(30_000);
+  assert.equal(
+    await touchEditor(projectId, editorId, revision, registrationCapability),
+    true,
+    'touch accepts the registered editor',
+  );
+  mock.timers.setTime(60_000);
+  assert.equal(
+    isProjectConnected(projectId),
+    true,
+    'a validated touch refreshes the editor online lease',
+  );
+} finally {
+  mock.timers.reset();
+  resetExternalAgentBrokerForTest();
+}
+
 console.log('broker-poll-refresh.verify: ok');

server/external-agent/broker-registry.ts

@@ -165,6 +165,11 @@ export class EditorConnectionRegistry {
     if (!editor || editor.editorInstanceId !== editorInstanceId) return false;
     if (registrationCapability !== undefined
       && !capabilityMatches(editor.capability, registrationCapability)) return false;
+    // A successful touch proves the editor transport is alive: refresh the
+    // online lease so an idle-but-polling editor does not drop out of
+    // isConnected() after ONLINE_MS, which would reject new browser bindings
+    // while the registered editor still blocks the offline fallback.
+    editor.lastSeen = Date.now();
     if (editor.ownership) {
       const renewed = await renewProjectEditOwnership(editor.ownership, baseRevision ?? editor.baseRevision);
       if (renewed.status !== 'renewed') {