Migrate inventory GUIs

[minoneer]

Current inventory GUIs are convoluted and implicitly rely on fragile item meta. We introduced a modern, more robust system with the biome refactor. We should gradually refactor all item GUIs:

• 1. Island Group Members screen (displayPartyGUI)
• 2. Permissions screen for one party member (displayPartyPlayerGUI)
• 3. Island Log screen (displayLogGUI)
• 4. Challenge Menu screen (displayChallengeGUI)
• 5. Island Menu / Island Create Menu flow (displayIslandGUI, createInitMenu, createMainMenu)
• 6. Island Restart Menu screen (createRestartGUI)
• 7. Config-driven extra menu entries in main menu (addExtraMenus + click action matching) - may be entirely redundant.

Supporting legacy click router that should disappear as screens move to button consumers:

• Global legacy menu click handler entry (MenuEvents.java:24)
• Legacy title/slot/type routing in SkyBlockMenu.onClick and subhandlers (SkyBlockMenu.java:691)