feat: hover menu with explain and chat buttons for editor content

[akshatbatra]

Closes #393

Addition of hover menu with Explain and Chat buttons for code in TemplateMark, Concerto and JSON Data editors.

Changes

• Explain button that opens an inline popup within the editor for explaining selected code.
• Chat button sends the code to chat window for explanation, user can ask follow up questions via this method.
• Code selection hover menu (explain and chat buttons) can be disabled/enabled in advanced settings of AI Assistant.
• Message rendering has been improved. Formatting of LLM responses had to improved for inline popup, this resulted in better rendering for all assistant responses in the chat panel too.

Author Checklist

• Ensure you provide a DCO sign-off for your commits using the --signoff option of git commit.
• Vital features and changes captured in unit and/or integration tests
• Commits messages follow AP format
• Extend the documentation, if necessary
• Merging to main from fork:branchname

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[sanketshevkar]

LGTM