[BUG] Set-Up包卸载后，对旧配置难以兼容，导致FlClash打开时仅一片空白

问题描述 / Describe the bug

问题截图：

问题描述：
旧版本FlClash，升级新包后，使用Set-Up包运行unins000.exe，提示有部分可以手动删除后，删除整个FlClash，后续使用Portable或Set-Up包运行FlClash.exe，出现如图所示情况。

个人目前的解决方案：

（ !!!!! 请务必保留好订阅配置的订阅链接 !!!!! ）

需将以下路径的文件删除
C:\Users\Administrator\AppData\Roaming\com.follow\clash

软件版本 / Version

FlClash 可能是任何低版本

复现步骤 / To Reproduce

安装旧版本FlClash，导入配置，接着升级新包，随后运行unins000.exe。
待提示有部分可以手动删除后，手动删除整个FlClash。
后续使用Portable或Set-Up包运行FlClash.exe，仅弹出白色窗口。

操作系统 / OS

Windows

操作系统版本 / OS Version

Win10

日志(勿上传日志文件，请粘贴日志内容) / Log (Do not upload the log file, paste the log content directly)

捕获错误日志：

①cd /d D:\FlClash
②FlClash.exe > log.txt 2>&1

错误日志：
FlClash\output.txt
↓↓↓↓↓
[ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: type 'int' is not a subtype of type 'String?' in type cast #0 _$ConfigFromJson (package:fl_clash/models/generated/config.g.dart:336) #1 new Config.fromJson (package:fl_clash/models/config.dart:258) #2 new Config.compatibleFromJson (package:fl_clash/models/config.dart:277) #3 Preferences.getConfig (package:fl_clash/common/preferences.dart:40) #4 GlobalState.init (package:fl_clash/state.dart:134) #5 GlobalState.initApp (package:fl_clash/state.dart:85) #6 main (package:fl_clash/main.dart:17)

Start with the compatibility path in lib/common/preferences.dart and lib/models/config.dart, then inspect the deserialization failure at lib/models/generated/config.g.dart:336. Reproduce the upgrade, uninstall, and relaunch sequence on Windows with an older configuration. Done means the existing configuration no longer causes a blank window or the reported type-cast exception.