feat: 重构主题管理并优化UI样式

重构主题管理逻辑，将useTheme composable迁移至pinia store中管理
更新页面布局和样式，调整边距和卡片样式
添加新的主题配置文件并移除旧的主题图片资源
优化登录页和设置页的UI交互
更新unocss配置添加更多flex快捷类

fastapp/vite.config.ts

@@ -3,6 +3,7 @@ import uni from "@dcloudio/vite-plugin-uni";
 import AutoImport from "unplugin-auto-import/vite";
 import UniLayouts from "@uni-helper/vite-plugin-uni-layouts";
 import UniPages from "@uni-helper/vite-plugin-uni-pages";
+
 import Components from "@uni-helper/vite-plugin-uni-components";
 import { WotResolver } from "@uni-helper/vite-plugin-uni-components/resolvers";