chore: tailwind prettier 플러그인 추가

Author: yewonJin

frontend/.prettierrc

@@ -0,0 +1,5 @@
+{
+  "printWidth": 80,
+  "tabWidth": 2,
+  "plugins": ["prettier-plugin-tailwindcss"]
+}

frontend/package.json

@@ -29,6 +29,8 @@
     "eslint-plugin-react-hooks": "^5.0.0",
     "eslint-plugin-react-refresh": "^0.4.14",
     "globals": "^15.11.0",
+    "prettier": "^3.3.3",
+    "prettier-plugin-tailwindcss": "^0.6.8",
     "typescript": "~5.6.2",
     "typescript-eslint": "^8.11.0",
     "vite": "^5.4.10"