refactor: reorganize config UI with headers and logical grouping

[Xerrion]

Summary

• Added header separators and description text to every tab for visual clarity
• Merged Combat (1 option) into General tab and ElvUI (1 option) into Appearance tab
• Reorganized Display (Layout > Size > Content > Position), Appearance (Font > Background > Border & Glow > Icon > ElvUI), Filters (Quality > Sources > Rewards), and Animation (General > Timing > Entrance) tabs with logical grouping
• Improved option labels (e.g. Slide Direction, Reposition Speed, Primary Font Size) and reduced tab count from 8+Profiles to 6+Profiles