Add responsible usage section

[marcoscaceres]

Closes #120

This pull request adds new guidance to the documentation about responsible badge usage. The update emphasizes the importance of minimizing notification fatigue and ensuring accessibility for all users.

Badge usage guidelines for authors:

• Added a new section under the heading "Responsible badge usage" to advise authors to reserve badges for important states and avoid using them for marketing or engagement purposes.
• Included recommendations to avoid rapidly changing badge values that could distract users or increase cognitive load.
• Encouraged authors to provide accessible alternatives for users who do not perceive badges, such as in-app status indicators with clear labels.

---

Preview | Diff

[Copilot]

Pull Request Overview

This pull request adds a new "Responsible badge usage" section to the documentation that provides guidance for authors on appropriate badge usage practices. The update focuses on preventing notification fatigue and ensuring accessibility for all users.

• Introduces guidance on reserving badges for important states rather than marketing purposes
• Recommends avoiding rapidly changing badge values to reduce cognitive load
• Emphasizes providing accessible alternatives for users who cannot perceive badges

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}