feat(server): KB prompt优化、字幕修复、S2S重连、助手配置API

- assistantProfileConfig: KB answer prompt改为分层策略(严格产品信息+灵活常识补充)
- nativeVoiceGateway: S2S upstream自动重连(最多50次)、event 351字幕debounce(800ms取最长文本)
- toolExecutor: 确定性query改写增强、KB查询传递session上下文
- contextKeywordTracker: 支持KB话题记忆优先enrichment
- contentSafeGuard: 新增品牌安全内容过滤服务
- assistantProfileService: 新增助手配置CRUD服务
- routes/assistantProfile: 新增助手配置API路由
- knowledgeKeywords: 扩展KB关键词词典
- fastAsrCorrector: ASR纠错规则更新
- tests/: KB prompt测试、保护窗口测试、Viking性能测试
- docs/: 助手配置API文档、系统提示词目录

test2/server/app.js

@@ -4,6 +4,7 @@ const express = require('express');
 const cors = require('cors');
 const path = require('path');
 const db = require('./db');
+const assistantProfileRoutes = require('./routes/assistantProfile');
 const voiceRoutes = require('./routes/voice');
 const chatRoutes = require('./routes/chat');
 const sessionRoutes = require('./routes/session');
@@ -52,6 +53,7 @@ function validateEnv() {
     { key: 'VOLC_WEBSEARCH_API_KEY', desc: '联网搜索' },
     { key: 'VOLC_S2S_SPEAKER_ID', desc: '自定义音色' },
     { key: 'VOLC_ARK_KNOWLEDGE_BASE_IDS', desc: '方舟私域知识库（语音）' },
+    { key: 'ASSISTANT_PROFILE_API_URL', desc: '外接助手资料接口' },
   ];
   const configuredOptional = optional.filter(({ key }) => {
     const v = process.env[key];
@@ -86,6 +88,7 @@ app.use((req, res, next) => {
   next();
 });
 
+app.use('/api/assistant-profile', assistantProfileRoutes);
 app.use('/api/voice', voiceRoutes);
 app.use('/api/chat', chatRoutes);
 app.use('/api/session', sessionRoutes);