feat(web): 接入 ESLint 与 vitest，TrendChart hover 读数

- ESLint（flat config，vue essential + ts recommended）接入并清零：
  webauthn.ts 标注为刻意的动态类型边界（文件级豁免），theme-init.js
  修掉未用的 catch 变量
- vitest + jsdom 接入，build 前置跑测试；覆盖 format 工具、auth store
  （token 只存内存、bootstrap 恢复、遗留键清理）、client.ts 401 拦截器
  single-flight（自定义 axios adapter 模拟 401→refresh→重放）
- TrendChart：hover 命中区盖满槽位（窄条也可悬停），读数显示在头部行，
  标签行联动高亮
- auth store bootstrap 顺手清理旧版 localStorage 遗留的 access token 键

web/package.json

@@ -5,8 +5,10 @@
   "type": "module",
   "scripts": {
     "dev": "vite",
-    "build": "vue-tsc -b && vite build",
-    "preview": "vite preview"
+    "build": "vue-tsc -b && vitest run --silent && vite build",
+    "preview": "vite preview",
+    "lint": "eslint .",
+    "test": "vitest run"
   },
   "dependencies": {
     "@fontsource-variable/geist": "^5.2.5",
@@ -21,9 +23,14 @@
     "@tailwindcss/vite": "^4.0.0",
     "@types/node": "^22.10.0",
     "@vitejs/plugin-vue": "^5.2.1",
+    "@vue/eslint-config-typescript": "^14.9.0",
+    "eslint": "^10.13.0",
+    "eslint-plugin-vue": "^10.12.0",
+    "jsdom": "^30.1.3",
     "tailwindcss": "^4.0.0",
     "typescript": "~5.6.2",
     "vite": "^6.0.0",
+    "vitest": "^5.0.5",
     "vue-tsc": "^2.1.10"
   }
 }