Major refactoring of Core.lua with significant performance and maintainability improvements:
- Cache global functions at module load for faster access
- Pre-compute all 128 school mask display strings on startup
- Implement message cache to avoid repeat formatting during combat
- Enhance localization support for Russian and English
- Add hyperlink/tooltip support for spell links
- Improve player identity tracking with PLAYER_ENTERING_WORLD event
- Better database initialization with type checking
- Simplify XML to just load Lua (event handling now in Lua)
- Improve code organization with named functions
