docs: improve configuration documentation format

[repparw]

This PR improves the README configuration documentation to better match Hyprland's documentation style:

Changes Made

• Restructured configuration section: Organized variables into logical categories (Colors, Layout, Visibility, Animation, Behavior)
• Added proper tables: Each section now uses tables with columns for variable name, description, type, and default values
• Simplified variable names: Removed repetitive plugin:overview: prefix from table entries and added clear instruction that options go under plugin:overview
• Improved descriptions: Made descriptions more concise and professional
• Added type information: Each variable now shows its expected type (bool, int, float, color, string)
• Better organization: Related variables are grouped together with clear subsection headings
• Consistent formatting: Follows Hyprland's documentation patterns for better user experience

The new format makes it much easier for users to understand and configure the plugin, following the same patterns as Hyprland's official documentation.

Closes #179

[repparw]

This was almost completely done by Copilot, so I don't know if the default values of each option are actually okay.