fix(whatsapp): unify contact identity and reduce realtime latency

server/src/ai.js

@@ -71,7 +71,7 @@ export async function deepseek(system, user, jsonOrOptions = false) {
 
 export function conversationContext(messages, limit = 30) {
   return messages.slice(-limit).map((m) => {
-    const role = m.sender === 'agent' ? '坐席' : m.sender === 'system' ? '系统' : '客户'
+    const role = m.sender === 'agent' ? '我方' : m.sender === 'system' ? '系统' : '对方'
     const content = m.originalText || m.attachmentName || `[${m.type || '消息'}]`
     const translation = m.translatedText && m.translatedText !== content ? `（译文：${m.translatedText}）` : ''
     return `${m.createdAt || ''} ${role}: ${content}${translation}`