Add Maxlength module to Varbase Admin Base recipe

Problem/Motivation

Drupal CMS and Varbase Admin Base includes Length Indicator but does not provide field-level maxlength enforcement. Editors can exceed recommended limits for text fields, which may lead to inconsistent content length and layout issues.

Proposed resolution

Add the Maxlength module to Varbase Admin Base recipe to provide UI-level maxlength enforcement for text fields alongside the length indicator.

Remaining tasks

• ✅ File an issue about this project
• ✅ Addition/Change/Update/Fix to this project
• ✅ Testing to ensure no regression
• ✅ Automated unit/functional testing coverage
• ✅ Developer Documentation support on feature change/addition
  
  Varbase Admin Base recipe
• ➖ User Guide Documentation support on feature change/addition
• ➖ UX/UI designer responsibilities
• ➖ Accessibility and Readability
• ✅ Code review from 1 Varbase core team member
• ✅ Full testing and approval
• ✅ Credit contributors
• ✅ Review with the product owner
• ✅ Update Release Notes
• ❌ Release varbase-11.0.0-alpha1, varbase_starter-1.0.0-alpha1, varbase_admin_base-1.0.0-alpha1

User interface changes

• Text fields will enforce maxlength with visual counter.

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• feat: #3586250 Add Maxlength module to Varbase Admin Base recipe