feat: upgrade ESLint to version 9

Author: pospisilf

.eslintrc.json

@@ -0,0 +1,41 @@
+// eslint.config.mjs
+
+import { defineConfig } from 'eslint-define-config';
+import ts from '@typescript-eslint/parser';
+import tsEslint from '@typescript-eslint/eslint-plugin';
+import stylisticEslint from '@stylistic/eslint-plugin';
+
+export default defineConfig([
+	{
+		ignores: ['**/*.test.js'],
+	},
+	{
+		files: ['**/*.ts', '**/*.tsx'],
+		languageOptions: {
+			parser: ts,
+			parserOptions: {
+				ecmaVersion: 2024,
+				project: './tsconfig.json',
+				createDefaultProgram: true,
+				ecmaFeatures: {
+					impliedStrict: true,
+				},
+			},
+		},
+		plugins: {
+			'@typescript-eslint': tsEslint,
+			'@stylistic': stylisticEslint,
+		},
+		rules: {
+			'@typescript-eslint/naming-convention': 'warn',
+			'@typescript-eslint/no-unused-expressions': 'off',
+			'@stylistic/semi': 'warn',
+			'curly': 'warn',
+			'eqeqeq': ['warn', 'always'],
+			'no-redeclare': 'warn',
+			'no-throw-literal': 'warn',
+			'no-unused-expressions': 'off',
+		},
+		ignores: ['src/ui-test/resources/problems.ts'],
+	},
+]);