feat: persist context snapshots and defer permission changes to next messages

scripts/chat-store-regression.ts

@@ -695,6 +695,7 @@ async function testEarlyOrderedEventsAndDuplicateGuard(): Promise<void> {
   const result = sendResult('run-order')
   const response = deferred<SendResult>()
   let sendCalls = 0
+  const enteredSend = deferred<void>()
   const events: ChatEvent[] = [
     { runId: 'other-run', type: 'text', delta: 'must be ignored' },
     { runId: result.runId, type: 'text', delta: 'before' },
@@ -715,6 +716,7 @@ async function testEarlyOrderedEventsAndDuplicateGuard(): Promise<void> {
 
   installFakeWindow(async () => {
     sendCalls++
+    enteredSend.resolve()
     for (const event of events) useChatStore.getState().applyEvent(event)
     return response.promise
   })
@@ -723,10 +725,19 @@ async function testEarlyOrderedEventsAndDuplicateGuard(): Promise<void> {
   assert.equal(useChatStore.getState().sending, true, 'sending should cover the pending IPC request')
   assert.equal(useChatStore.getState().messages.length, 0, 'early events wait for the send result placeholder')
   await assert.rejects(useChatStore.getState().send('duplicate'), /提交/)
+  // The duplicate rejects synchronously; preference persistence/capture may still
+  // be settling. Observe the actual IPC boundary rather than count microtasks.
+  let deadline: ReturnType<typeof setTimeout> | undefined
+  try {
+    await Promise.race([enteredSend.promise, new Promise<never>((_, reject) => {
+      deadline = setTimeout(() => reject(new Error('first send did not reach IPC')), 2000)
+    })])
+  } finally { clearTimeout(deadline) }
   assert.equal(sendCalls, 1, 'a second send must be ignored while the first send is pending')
 
   response.resolve(result)
   await firstSend
+  assert.equal(sendCalls, 1, 'duplicate must never reach IPC after the first submission completes')
 
   const message = assistantMessage()
   assert.equal(message.turnStartedAt, undefined, 'terminal events clear the live timer timestamp')