Experiment in more dynamic Item/Fluid logistics for GregTech modern.

• Target GTCEu 7.5.x APIs for Minecraft 1.20.1. Do not use earlier GTCEu APIs as implementation references.
• For Chubes-owned real config inventories, use LDLib ItemStackTransfer with LDLib SlotWidget. Avoid binding Forge ItemStackHandler directly to config slots.
• Keep LDLib UI widget trees deterministic between server and client. Client-only tab state or conditionally-created slots can desync native container slot ids.
• In synced LDLib UIs, prefer LabelWidget string/supplier constructors. The Component constructor can leave textSupplier unset and crash server-side detectAndSendChanges.