Add pretter config and CI

Author: JasonGrace2282

.pre-commit-config.yaml

@@ -30,3 +30,8 @@ repos:
         name: ruff lint
       - id: ruff-format
         files: ^tin/.*
+  - repo: https://github.com/pre-commit/mirrors-prettier
+    rev: v2.5.1
+    hooks:
+      - id: prettier
+        types_or: [ javascript, css ]

.prettierrc.js

@@ -0,0 +1,9 @@
+/** @type {import("prettier").Config} */
+const config = {
+  trailingComma: 'es5',
+  tabWidth: 2,
+  semi: true,
+  singleQuote: true,
+};
+
+module.exports = config;