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/routes/assistantProfile.js

@@ -0,0 +1,65 @@
+const express = require('express');
+const router = express.Router();
+const { getAssistantProfile, clearAssistantProfileCache } = require('../services/assistantProfileService');
+
+router.get('/', async (req, res) => {
+  try {
+    const userId = String(req.query.userId || '').trim() || null;
+    const forceRefresh = String(req.query.forceRefresh || '').trim() === 'true';
+    const result = await getAssistantProfile({ userId, forceRefresh });
+    res.json({
+      code: 0,
+      message: 'success',
+      success: true,
+      data: {
+        userId,
+        profile: result.profile,
+        source: result.source,
+        cached: result.cached,
+        fetchedAt: result.fetchedAt,
+        configured: result.configured,
+        error: result.error,
+      },
+    });
+  } catch (error) {
+    console.error('[AssistantProfile] query failed:', error.message);
+    res.status(500).json({
+      code: 500,
+      message: error.message,
+      success: false,
+      error: error.message,
+    });
+  }
+});
+
+router.post('/refresh', async (req, res) => {
+  try {
+    const userId = String(req.body?.userId || '').trim() || null;
+    clearAssistantProfileCache(userId);
+    const result = await getAssistantProfile({ userId, forceRefresh: true });
+    res.json({
+      code: 0,
+      message: 'success',
+      success: true,
+      data: {
+        userId,
+        profile: result.profile,
+        source: result.source,
+        cached: result.cached,
+        fetchedAt: result.fetchedAt,
+        configured: result.configured,
+        error: result.error,
+      },
+    });
+  } catch (error) {
+    console.error('[AssistantProfile] refresh failed:', error.message);
+    res.status(500).json({
+      code: 500,
+      message: error.message,
+      success: false,
+      error: error.message,
+    });
+  }
+});
+
+module.exports = router;