Reapply "fix(abut): 날개벽의 연직 헌치 삭제"

This reverts commit 4b51ef186f.

tests/abut-scene.test.ts

@@ -21,13 +21,13 @@ const group = buildAbutGroup(model, members, wings);
 const count = (name: string) => (group.getObjectByName(name) as THREE.Group | undefined)?.children.length ?? 0;
 
 describe('교대 A1 3D 장면 (AA3·AA3b·AA3c)', () => {
-  it('has the members: 5 wall blocks, 10 parapet parts (2 per step), 1 footing, 18 piles, 2 wings, 6 haunches', () => {
+  it('has the members: 5 wall blocks, 10 parapet parts (2 per step), 1 footing, 18 piles, 2 wings, 2 haunches (저판 상면)', () => {
     expect(count('wall')).toBe(5); // one 벽체 block per 교좌면 step (삽도)
     expect(count('parapet')).toBe(10); // per step: back strip (흉벽 배면 단차) and the 흉벽 (삽도)
     expect(count('footing')).toBe(1);
     expect(count('piles')).toBe(18);
     expect(count('wings')).toBe(4); // upper and lower part per wing
-    expect(count('haunches')).toBe(6); // per wing: upper and lower 연직 헌치, and the 저판 상면 헌치
+    expect(count('haunches')).toBe(2); // per wing: the 저판 상면 헌치
   });
 
   it('spans from the pile tip (19.295 m) up to the highest parapet end (47.18 m)', () => {