sllight hub overhaul

redid the project hub screen and added recent projects tracking, since up to now opening anything meant going through a file dialog every single time…

changes

• recent projects get tracked in a PROJECTHIST file (next to the editor executable) …dead simple format, one filepath per line, each pointing at a project’s .json. capped at 5 entries, oldest just get removed off the list.
• hub screen is basically remade two docked panels now instead of one. left panel is the same buttons as before (new project, open project, etc), right panel is the new recent-projects list, up to 5 entries since that’s all the history file holds.

also

• removed some unused dead code i found…

QoL type stuff i guess :D