chore(web,server): 移除全套AI助手功能相关代码

删除后端AI助手服务文件及对应的/api/ai-assistant接口路由，移除前端ai-assistant.js脚本及所有HTML页面中的脚本引用，清理静态资源版本配置文件里的相关配置项，同时更新bump-web-asset-version.js脚本的示例命令与错误提示文本。

server/routes/api.js

@@ -3,7 +3,6 @@ const crypto = require('crypto');
 const router = express.Router();
 const DataService = require('../services/data');
 const LogicService = require('../services/logic');
-const AIAssistantService = require('../services/ai-assistant');
 const io = require('../io');
 
 // Helper to get IP
@@ -161,53 +160,6 @@ router.get('/config', (req, res) => {
   });
 });
 
-router.post('/ai-assistant', async (req, res) => {
-  try {
-    const message = String(req.body?.message || '').trim();
-    if (!message) return res.status(400).json({ ok: false, error: 'message required' });
-
-    const result = await AIAssistantService.askAssistant({
-      message,
-      history: req.body?.history,
-      page: req.body?.page,
-      context: req.body?.context,
-      config: DataService.getConfig(),
-      stations: DataService.getStations(),
-      lines: DataService.getLines(),
-      fares: DataService.getFares()
-    });
-
-    appendReqLog(req, {
-      category: 'public',
-      type: 'ai_assistant_ask',
-      detail: {
-        page: String(req.body?.page || '').trim(),
-        question: message.slice(0, 280),
-        model: result.model
-      }
-    });
-    res.json({ ok: true, reply: result.reply, model: result.model });
-  } catch (e) {
-    const code = e?.code || '';
-    const status = code === 'INVALID_MESSAGE' ? 400 : (code === 'AI_NOT_CONFIGURED' ? 503 : 500);
-    appendReqLog(req, {
-      category: 'system',
-      type: 'ai_assistant_failed',
-      level: status >= 500 ? 'error' : 'warn',
-      detail: {
-        page: String(req.body?.page || '').trim(),
-        error: e?.message || String(e)
-      }
-    });
-    res.status(status).json({
-      ok: false,
-      error: code === 'AI_NOT_CONFIGURED'
-        ? 'AI 助手尚未配置 DeepSeek API Key'
-        : (e?.message || 'ai assistant request failed')
-    });
-  }
-});
-
 router.put('/config', async (req, res) => {
   try {
     const incoming = req.body || {};