fix(schedule): close absolute-time review gaps

packages/host/apiproxy/tests/api-proxy-subagents.spec.ts

@@ -50,7 +50,10 @@ function bench(options: {
     _parent: unknown,
     _childId: SessionId,
     _content: unknown,
-    _delivery: { source: { kind: string; rpcId: RpcId }; signal: AbortSignal },
+    _delivery: {
+      source: { kind: string; rpcId: RpcId; clientTimeZone?: string }
+      signal: AbortSignal
+    },
   ) => options.followupError === undefined
     ? Promise.resolve('message-1')
     : Promise.reject(options.followupError))
@@ -270,6 +273,43 @@ describe('subagent gateway', () => {
     )
   })
 
+  it('canonicalizes browser-zone provenance before delivering a child prompt', async () => {
+    const { api, parent, followup } = bench()
+    const alias = 'US/Pacific'
+    const canonical = new Intl.DateTimeFormat('en-US', { timeZone: alias })
+      .resolvedOptions().timeZone
+    const content = [{ type: 'text' as const, text: 'continue locally' }]
+    const signal = new AbortController().signal
+    await expect(api.subagents.prompt(request({
+      parentSessionId: PARENT,
+      childSessionId: CHILD,
+      mode: 'continuable',
+      content,
+      clientTimeZone: alias,
+    }), signal)).resolves.toMatchObject({ result: { ok: true } })
+    expect(followup).toHaveBeenCalledWith(parent, CHILD, content, {
+      source: { kind: 'user', rpcId: RpcId('subagent-rpc'), clientTimeZone: canonical },
+      signal,
+    })
+
+    const invalid = await api.subagents.prompt(request({
+      parentSessionId: PARENT,
+      childSessionId: CHILD,
+      mode: 'continuable',
+      content,
+      clientTimeZone: 'Not/A_Real_Zone',
+    }), signal)
+    expect(invalid.result).toEqual({
+      ok: false,
+      error: {
+        code: 'invalid-time-zone',
+        message: 'clientTimeZone must be UTC or a valid IANA Area/Location name',
+        details: { value: 'Not/A_Real_Zone' },
+      },
+    })
+    expect(followup).toHaveBeenCalledOnce()
+  })
+
   it('fails before delivery when the parent is absent and maps continuation failures', async () => {
     const absent = bench({ parentLive: false })
     expect((await absent.api.subagents.prompt(request({