chore: 移除未使用的 ui-icon-detect 模型(80MB)

- webpage-element.onnx 为实测首选模型，运行时永远先命中；
  ui-icon-detect/model.onnx 仅作为老安装包兜底回退，无实际使用场景
- 删除模型目录（含无引用的 preprocessor_config.json），运行时去掉兜底候选
- 上一个提交给打包加的 ui-icon-detect 拷贝行随之移除
- 注：git 历史中该 blob 仍存在（不做历史改写），仅工作区与新 clone 不再需要下载该模型

electron-builder.config.mjs

@@ -29,7 +29,6 @@ export default {
     { from: path.join(root, "resources", "capability-duplicates.json"), to: "capability-duplicates.json" },
     { from: path.join(root, "resources", "desktop-picker.ps1"), to: "desktop-picker.ps1" },
     { from: path.join(root, "resources", "models", "ui-element-detect"), to: "models/ui-element-detect" },
-    { from: path.join(root, "resources", "models", "ui-icon-detect"), to: "models/ui-icon-detect" },
     { from: path.join(root, "resources", "fixture"), to: "fixture" }
   ],
   asar: true,