Fix ESLint TypeScript parsing: add @typescript-eslint/parser, resolve all lint errors

Co-authored-by: Stan2032 <68326386+Stan2032@users.noreply.github.com>

Author: Copilot

eslint.config.js

@@ -2,12 +2,14 @@ import js from '@eslint/js'
 import globals from 'globals'
 import reactHooks from 'eslint-plugin-react-hooks'
 import reactRefresh from 'eslint-plugin-react-refresh'
+import tsParser from '@typescript-eslint/parser'
+import tsPlugin from '@typescript-eslint/eslint-plugin'
 import { defineConfig, globalIgnores } from 'eslint/config'
 
 export default defineConfig([
   globalIgnores(['dist']),
   {
-    files: ['**/*.{js,jsx,ts,tsx}'],
+    files: ['**/*.{js,jsx}'],
     ignores: ['backend/**', 'src/test/**'],
     extends: [
       js.configs.recommended,
@@ -28,6 +30,34 @@ export default defineConfig([
       'react-refresh/only-export-components': 'warn',
     },
   },
+  {
+    files: ['**/*.{ts,tsx}'],
+    ignores: ['backend/**', 'src/test/**'],
+    extends: [
+      js.configs.recommended,
+      reactHooks.configs.flat.recommended,
+      reactRefresh.configs.vite,
+    ],
+    languageOptions: {
+      ecmaVersion: 2020,
+      globals: globals.browser,
+      parser: tsParser,
+      parserOptions: {
+        ecmaVersion: 'latest',
+        ecmaFeatures: { jsx: true },
+        sourceType: 'module',
+      },
+    },
+    plugins: {
+      '@typescript-eslint': tsPlugin,
+    },
+    rules: {
+      'no-unused-vars': 'off',
+      'no-undef': 'off',
+      '@typescript-eslint/no-unused-vars': ['error', { varsIgnorePattern: '^([A-Z_]|motion$)', argsIgnorePattern: '^(_|[A-Z])', destructuredArrayIgnorePattern: '^_' }],
+      'react-refresh/only-export-components': 'warn',
+    },
+  },
   {
     files: ['public/sw.js'],
     languageOptions: {