fix(agent): inject Shanghai time into each reply message

103 goosed harness_remember returns remembered:false, so session memory
never carried the time anchor. Prepend buildCurrentTimeAgentPrefix on every
H5 /reply and WeChat agent prompt so the model sees Asia/Shanghai clock.

Co-authored-by: Cursor <cursoragent@cursor.com>

user-memory-profile.test.mjs

@@ -12,6 +12,7 @@ import {
   resolveTimeOfDayPeriod,
   suggestCodeExecutorForTask,
   buildSessionMemoryEntries,
+  buildCurrentTimeAgentPrefix,
   ensureUserMemoryProfile,
   hasMemoryStore,
   loadUserMemoryProfile,
@@ -123,6 +124,16 @@ test('buildSessionMemoryEntries injects time anchor even without memory store',
   assert.match(entries[0].content, /13:00（中午）/);
 });
 
+test('buildCurrentTimeAgentPrefix wraps Shanghai anchor for agent-only injection', () => {
+  const text = buildCurrentTimeAgentPrefix({
+    now: Date.UTC(2026, 5, 29, 5, 0, 0),
+    timezone: 'Asia/Shanghai',
+  });
+  assert.match(text, /不要向用户复述/);
+  assert.match(text, /2026-06-29（星期一）/);
+  assert.match(text, /13:00（中午）/);
+});
+
 test('renderCurrentTimeAnchor formats Shanghai weekday from exact date', () => {
   const text = renderCurrentTimeAnchor({
     now: Date.UTC(2026, 5, 29, 5, 0, 0),