[SWG] Simple Waystones Groups

[1.0.0] - Initial Release

• Groups for waystones: create, rename, delete groups and assign waystones
• Filter waystone selection list by group (Waystone menu only; Sharestones/Portstones unchanged)
• Visibility filter: All / Everyone / Activated by me
• Last selected group and visibility remembered per world/server (saved in config)
• Client-only mode: groups stored locally in config/simplewaystonesgroups_groups.json when the mod is not on the server
• Optional server-side: when the mod is on the server, groups persist in the world and sync on join
• Edit Group screen: waystone names shown as inactive buttons, remove (X) per row, Add/Rename/Save