Enhance Documentation to Include AI Assistant Disablement Instructions

[Blaec-CoCalc]

Is your feature request related to a problem? Please describe.
Enhancing user knowledge about disabling AI Assistant. Users may not be aware of the ability to disable the AI Assistant at the account and project levels, which can lead to unnecessary frustrations.

Describe the solution you'd like
Update the documentation to clearly mention the ability to disable the AI Assistant:

• For personal accounts in the Account Preferences.
• For projects (especially for course instructors), add it to the Instructor Guide FAQ with instructions via the .course file's course configuration tab.
• Include cross-links on the AI page and How-tos page to ensure all related docs are interconnected.

Describe alternatives you've considered
Adding a dedicated section regarding AI Assistant settings on all relevant documentation pages.

Additional context
Improving visibility of these functionalities can empower users and educators to better manage their CoCalc environments according to personal or course-specific needs. Providing cross-references in the documentation will enhance the user's ability to find and utilize these features efficiently.