fix architecture and write new tests

apps/admin/vitest.config.ts

@@ -0,0 +1,17 @@
+import { fileURLToPath } from 'node:url'
+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+  resolve: {
+    alias: {
+      '@': fileURLToPath(new URL('./src', import.meta.url)),
+    },
+  },
+  test: {
+    environment: 'node',
+    globals: true,
+    include: ['src/**/*.test.ts'],
+    clearMocks: true,
+    restoreMocks: true,
+  },
+})