Use resizable square defaults for Harbor wall ability

- switch Harbor last ability to `ResizableSquareAbility`
- set min length, default-to-max behavior, and top border
- add Harbor default behavior coverage in resizable square tests
991f04d02bDara Adedeji committed on 3/10/2026, 1:39:53 PMparent71fee3c
2 files changedLine totals unavailable