rack：字体打包进前端（Noto Sans SC 可变 + Barlow），各端统一

图表 init 前先 document.fonts.load 字形：zrender 按字体缓存文字宽度且不清空，
字体未到就量会让时间轴标签叠成一团。

Co-Authored-By: Claude Opus 5.5 <[email protected]>

rack/frontend/package.json

@@ -10,6 +10,8 @@
   },
   "dependencies": {
     "@element-plus/icons-vue": "^2.3.1",
+    "@fontsource-variable/noto-sans-sc": "^5.3.0",
+    "@fontsource/barlow": "^5.3.0",
     "echarts": "^5.6.0",
     "element-plus": "^2.9.0",
     "vue": "^3.5.0",