Add the league/commonmark library to allow formats messages in the AI Chatbot module

Problem/Motivation

Listed and suggested in the Drupal AI module

    "suggest": {
        "league/commonmark": "Allows previewing of chunked content when configuring the fields to be indexed in AI Search, and formats messages in the AI Chatbot module."
    }

league/commonmark is a highly-extensible PHP Markdown parser created by Colin O'Dell which supports the full CommonMark spec and GitHub-Flavored Markdown.

Proposed resolution

Add league/commonmark to Varbase AI Agents
#3504871: Document that league/commonmark is needed for proper html

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
• ➖ 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 and Update Helper on new feature change/addition
• ✅ Release varbase-10.0.4, varbase_ai_agents-1.0.1

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• Issue #3502844: Added the league/commonmark library to allow formats messages in the AI Chatbot module