Add Prettier for TypeScript formatting

- Install prettier
- Configure .prettierrc.json and .prettierignore
- Add npm scripts: format, format:check
- Add Makefile target: format-frontend
- Format all frontend files

frontend/eslint.config.js

@@ -1,31 +1,26 @@
-import eslint from '@eslint/js';
-import tseslint from 'typescript-eslint';
-import reactHooks from 'eslint-plugin-react-hooks';
+import eslint from "@eslint/js";
+import tseslint from "typescript-eslint";
+import reactHooks from "eslint-plugin-react-hooks";
 
 export default tseslint.config(
   eslint.configs.recommended,
   ...tseslint.configs.recommended,
   {
     plugins: {
-      'react-hooks': reactHooks,
+      "react-hooks": reactHooks,
     },
     rules: {
       ...reactHooks.configs.recommended.rules,
-      '@typescript-eslint/no-unused-vars': [
-        'error',
-        { argsIgnorePattern: '^_', varsIgnorePattern: '^_' },
+      "@typescript-eslint/no-unused-vars": [
+        "error",
+        { argsIgnorePattern: "^_", varsIgnorePattern: "^_" },
       ],
       // Downgrade to warnings - existing patterns use these
-      'react-hooks/exhaustive-deps': 'warn',
-      'react-hooks/set-state-in-effect': 'off',
+      "react-hooks/exhaustive-deps": "warn",
+      "react-hooks/set-state-in-effect": "off",
     },
   },
   {
-    ignores: [
-      '.next/**',
-      'node_modules/**',
-      'app/generated/**',
-    ],
+    ignores: [".next/**", "node_modules/**", "app/generated/**"],
   }
 );
-