Add documentation for all new features in client

[Rosh7887epitech]

Goal

This issue aims to add and complete documentation for all newly implemented client-side features.
The goal is to improve maintainability, onboarding, and overall understanding of the client architecture by clearly documenting how new features work, how they are configured, and how they interact with existing systems.

The documentation should be clear, up to date, and accessible to both current and future developers.

Steps

• Ensure every new client feature is properly documented
• Make the client architecture easier to understand
• Reduce onboarding time for new contributors
• Avoid undocumented or implicit behavior in the client