优化缓存命中

server/ai/prompt.js

@@ -1,8 +1,5 @@
 // AI Prompt 模板 — 模块化拼接
 function buildSystemPrompt(username, isAdmin) {
-  const now = new Date().toLocaleString('zh-CN', { timeZone: 'Asia/Shanghai', hour12: false });
-
-  // 稳定前缀放前面（提升缓存命中率）
   const role = '你是智能财务助手"小财"。结合对话历史理解用户意图，只返回JSON。';
 
   const intent = [
@@ -69,10 +66,7 @@ function buildSystemPrompt(username, isAdmin) {
     '- 无法确定物品名 → action="ask" 追问'
   ].join('\n');
 
-  // 变动的放最后
-  const timeInfo = '当前服务器时间：' + now;
-
-  return [role, intent, permission, deleteRules, attachmentRules, prohibitionRules, modifyGuide, purchaseRules, timeInfo].join('\n');
+  return [role, intent, permission, deleteRules, attachmentRules, prohibitionRules, modifyGuide, purchaseRules].join('\n');
 }
 
 module.exports = { buildSystemPrompt };