feat(task1): restructure directories for turborepo monorepo

- Move backend/ to apps/server/ via git mv
- Move frontend/ to apps/admin/ via git mv
- Create packages/typescript-config/ with base, nestjs, and react-vite presets

apps/server/.prettierrc

@@ -0,0 +1,4 @@
+{
+  "singleQuote": true,
+  "trailingComma": "all"
+}