Convert ESLint config to flat config format

[Copilot]

ESLint 9 requires the new flat config format. The old .eslintrc JSON format is no longer supported.

Changes

• New eslint.config.js using flat config structure with @eslint/js and globals packages
• Removed .eslintrc (deprecated format)
• Migrated deprecated rules:
  • no-spaced-func → func-call-spacing
  • Removed rules no longer in ESLint 9: handle-callback-err, no-catch-shadow, no-native-reassign, newline-after-var, no-reserved-keys, no-wrap-func

Config structure

const globals = require( 'globals' );
const js = require( '@eslint/js' );

module.exports = [
  js.configs.recommended,
  {
    languageOptions: {
      sourceType: 'commonjs',
      ecmaVersion: 2021,
      globals: {
        ...globals.node,
        arguments: 'writable',
      },
    },
    rules: {
      // all existing rules preserved
    },
  },
];

Note: No additional devDependencies needed - @eslint/js and globals are now provided by dotest.

Original prompt

Convert the current old ESlint config to the new config format. Create a PR with the changes.

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[coveralls]

coverage: 100.0%. remained the same
when pulling f44c56f on copilot/convert-eslint-config-format
into 7e1f701 on develop.

[fvdm]

@copilot Run the test again that required the firewall changes

[Copilot]

@copilot Run the test again that required the firewall changes

Tests ran successfully - network access to www.googleapis.com is now working. ESLint with the new flat config shows 0 errors (1 pre-existing warning about unused eslint-disable directive in example.js).

The API tests reach Google's servers now but fail due to missing/invalid API key (expected without KEY env var). Error handling test (3/3) passes correctly.

[fvdm]

@copilot I have updated the 'dotest' dev dep for better ESLint v9 support. Please re-run your tests. Also I think the dev dep changes in the package.json are now no longer needed.

[Copilot]

@copilot I have updated the 'dotest' dev dep for better ESLint v9 support. Please re-run your tests. Also I think the dev dep changes in the package.json are now no longer needed.

Tests re-run with dotest 2.14.2 - ESLint works correctly with the flat config. Removed @eslint/js and globals from devDependencies since dotest now includes them (commit f44c56f).