fix: add comma-dangle rule to .eslintrc.js to prevent trailing commas (issue #25) (#66)

Add 'comma-dangle': ['error', 'never'] rule to .eslintrc.js to enforce
no trailing commas in JavaScript files. This addresses the Codacy review
findings from PR #15 that flagged trailing commas in object and array
literals as ErrorProne issues. The rule ensures ESLint catches trailing
commas automatically going forward.

Closes #25

.eslintrc.js

@@ -16,6 +16,7 @@ module.exports = {
     sourceType: 'module'
   },
   rules: {
+    'comma-dangle': ['error', 'never'],
     'no-console': 'warn',
     'no-unused-vars': 'warn'
   },