V71 CORNER-DIAGONAL SLIDER + COAST SHIFT

What changed
- The Corner pinch angle slider now tilts BOTH end petals.
- The slider semantics are inverted as requested: as the value goes toward 0, the end-petal direction approaches a 45-degree diagonal.
- UI text now shows both the slider value and the actual geometric tilt angle.
- Reset default is set so the actual tilt remains about 18 degrees (slider shows 27.0).

Coast override fix
- The previously moved land cell was shifted in the wrong vertical direction.
- From the current state, the land cell is moved 2 cells upward.
- Applied overrides:
  * 563,425 -> water
  * 564,424 -> water
  * 564,423 -> water
  * 564,422 -> land
