### Bug Fixes
- Fixed persistent blank tooltip when hovering over empty GUI slots by introducing a config toggle to disable filler panes.
- Hardened GUI protections to prevent moving items on Business GUI screens by cancelling both click and drag interactions while a `BusinessGUI` is open.
- Fixed broken/inconsistent UI screens by ensuring all Business GUI inventories use `BusinessGUIHolder` and validating top-inventory checks.

### Config
- New key in `config.yml`:
- `gui.useFillerPanes` (default: `true`) — when `false`, empty GUI slots are left empty to avoid hover tooltips.

### Notes
- Behavior for click/drag blocking in GUI is unchanged; interactions remain canceled while a `BusinessGUI` inventory is open.