expand configuration and module documentation with clarifications and corrections

[romanstingler]

Update multiple documentation files to clarify configuration options, module availability across compositors, and feature behavior. Key changes include:

• Expanded compositor support matrix with detailed feature availability notes
• Added warning about TOML None literal handling in configuration
• Documented module availability per backend (Hyprland, Niri, MangoWC, generic Wayland)
• Clarified custom module behavior, including Text vs Button type differences
• Updated system_info documentation with sensor label format and disk mount point requirements
• Refined settings module format options with detailed value descriptions
• Corrected tempo module documentation for weather location and wind speed units
• Added build and runtime dependency details for source compilation
• Updated intro with complete module feature lists
• Removed duplication