deps: upgrade ESLint toolchain to eslint v10 and @typescript-eslint v8 (#1073)

* deps: upgrade ESLint toolchain to eslint v10 and @typescript-eslint v8

- Bump eslint from 8.57.1 to 10.0.3
- Bump @typescript-eslint/eslint-plugin from 7.0.0 to 8.57.1
- Bump @typescript-eslint/parser from 6.21.0 to 8.57.1
- Bump eslint-plugin-mocha from 11.0.0 to 11.2.0
- Bump eslint-plugin-testing-library from 7.15.4 to 7.16.0
- Bump mocha from ^11.0.1 to ^11.7.5
- Bump nyc from 17.1.0 to 18.0.0

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(lint): migrate ESLint config to flat config format for ESLint v10

Replace .eslintrc.js and .eslintignore with eslint.config.js using the
new flat config API required since ESLint v9. Disable no-require-imports
(CJS project) and no-unused-expressions (Chai assertion pattern).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: thomaspoignant

.eslintignore

@@ -0,0 +1,22 @@
+const tsPlugin = require('@typescript-eslint/eslint-plugin');
+const tsParser = require('@typescript-eslint/parser');
+
+module.exports = [
+  {
+    ignores: ['example/', 'lib/', 'eslint.config.js'],
+  },
+  tsPlugin.configs['flat/eslint-recommended'],
+  ...tsPlugin.configs['flat/recommended'],
+  {
+    files: ['**/*.ts'],
+    languageOptions: {
+      parser: tsParser,
+    },
+    rules: {
+      '@typescript-eslint/no-explicit-any': 'off',
+      '@typescript-eslint/no-require-imports': 'off',
+      '@typescript-eslint/no-unused-expressions': 'off',
+      semi: [2, 'always'],
+    },
+  },
+];