feat: 部署到服务器+移动端适配+帮助系统RAG集成+网页图标

- 部署脚本 deploy.sh：一键部署到 154.8.162.18，端口3400，Nginx conf.d
- 应用名改为「企业用工专家」（登录/注册/侧边栏/员工端等6处）
- 移动端适配修复：Attendance/Dashboard/Settings/Contracts 6处grid响应式
- 帮助系统：HelpModal 组件 + TopNav 帮助图标 + RAG语义搜索集成
  - 后端 rag.service.ts 新增23条帮助种子数据 + searchHelp()
  - 前端搜索调用 /ai/rag/help-search，RAG不可用时回退关键词匹配
- 网页图标 favicon.svg（indigo主色+建筑人形图案）
- index.html 标题改为「企业用工专家」

backend/src/routes/ai.routes.ts

@@ -1,7 +1,7 @@
 import { Router } from 'express'
 import { authMiddleware, AuthRequest } from '../middleware/auth'
 import { chat, chatStream, reviewContract, matchCase, predictRisks, predictRisksStream, predictStructuredStream } from '../services/ai.service'
-import { seedKnowledgeBase, addKnowledge, searchKnowledge, ensureRAGTable } from '../services/rag.service'
+import { seedKnowledgeBase, addKnowledge, searchKnowledge, ensureRAGTable, searchHelp, seedHelpKnowledge } from '../services/rag.service'
 import prisma from '../lib/prisma'
 import { z } from 'zod'
 import { decrypt } from '../lib/crypto'
@@ -632,6 +632,30 @@ router.get('/rag/list', authMiddleware, async (req: AuthRequest, res, next) => {
   }
 })
 
+// 帮助文档 RAG 搜索（语义匹配）
+router.post('/rag/help-search', authMiddleware, async (req: AuthRequest, res, next) => {
+  try {
+    const { query, topK } = req.body
+    if (!query) {
+      return res.status(400).json({ success: false, error: { code: 'BAD_REQUEST', message: '缺少 query' } })
+    }
+    const results = await searchHelp(query, topK || 5)
+    res.json({ success: true, data: { results } })
+  } catch (err) {
+    next(err)
+  }
+})
+
+// 帮助文档初始化（注入帮助种子数据到 RAG 知识库）
+router.post('/rag/help-seed', authMiddleware, async (_req: AuthRequest, res, next) => {
+  try {
+    await seedHelpKnowledge()
+    res.json({ success: true, data: { message: '帮助文档已注入知识库' } })
+  } catch (err) {
+    next(err)
+  }
+})
+
 // 删除知识条目
 router.delete('/rag/:id', authMiddleware, async (req: AuthRequest, res, next) => {
   try {