Enhance Vitest configuration and improve Vue integration

- Added Vue plugin to vitest.config.ts for better component testing.
- Introduced vitest.setup.ts to expose Vue reactivity and lifecycle methods globally, ensuring compatibility with .vue components.
- Updated mock implementations in nuxt-imports.ts to include readonly for improved reactivity handling.
- Refactored useMapBookmarks and useToast composables to utilize readonly from Vue for better state management.

frontend-nuxt/__mocks__/nuxt-imports.ts

@@ -1,6 +1,26 @@
-import { ref, reactive, computed, watch, watchEffect, onMounted, onUnmounted, nextTick } from 'vue'
+import {
+  ref,
+  reactive,
+  computed,
+  watch,
+  watchEffect,
+  onMounted,
+  onUnmounted,
+  nextTick,
+  readonly,
+} from 'vue'
 
-export { ref, reactive, computed, watch, watchEffect, onMounted, onUnmounted, nextTick }
+export {
+  ref,
+  reactive,
+  computed,
+  watch,
+  watchEffect,
+  onMounted,
+  onUnmounted,
+  nextTick,
+  readonly,
+}
 
 export function useRuntimeConfig() {
   return {