Revert "feat(rebar): B1–B4와 B5–B8 방향 교환 (B1–B4는 W 방향, B5–B8은 L 방향)"

이 교환은 9,350 방향이 L이라는 가정에서 적용됐으나, 단면 삽도(B5–B8 선, 교각축 직각 단면)와 재료표가 원래 배치(B1–B4 L 방향, B5–B8 W 방향)와 맞는 것으로 확인되어 되돌림.

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>

tests/footing-rebar-settings.test.ts

@@ -20,8 +20,8 @@ describe('확대기초 배근 입력 (승인 2026-10-26, 시안 ③ 확대기초
   });
 
   it('the grid spacing s reaches the grid positions and the rebar table', () => {
-    const m = buildPier({ ...loadP1(), footingRebar: { sL: 150 } });
-    expect(m.footingRebar.sL).toBe(150);
+    const m = buildPier({ ...loadP1(), footingRebar: { sAxis: 150 } });
+    expect(m.footingRebar.sAxis).toBe(150);
     const xs = gridPositions(8000, m.footingRebar);
     expect(xs[1] - xs[0]).toBeCloseTo(150, 6);
     const b4 = rebarSummary(m).rows.find((r) => r.name === 'B4')!;
@@ -36,7 +36,7 @@ describe('확대기초 배근 입력 (승인 2026-10-26, 시안 ③ 확대기초
     const b10 = base.find((r) => r.name === 'B10-1')!;
     expect([b10.spacing, b10.basis]).toEqual(['200', 'default']);
 
-    const rows = rebarSummary(buildPier({ ...loadP1(), footingRebar: { sL: 150 } })).rows;
+    const rows = rebarSummary(buildPier({ ...loadP1(), footingRebar: { sAxis: 150 } })).rows;
     const b2s = rows.find((r) => r.name === 'B2')!;
     expect([b2s.spacing, b2s.actual, b2s.basis]).toEqual(['300', '150', 'input']);
     const b1s = rows.find((r) => r.name === 'B1')!;
@@ -44,20 +44,18 @@ describe('확대기초 배근 입력 (승인 2026-10-26, 시안 ③ 확대기초
     expect(rows.find((r) => r.name === 'B10-1')!.basis).toBe('default');
   });
 
-  // 방향 교환 (승인 2026-10-26): sL = spacing along L (B1–B4, B9 columns, B11); sW = spacing along W (B5–B8, B9 rows, B12).
-  it('방향 (교환 후): sW는 B5–B8·B12, sL은 B1–B4·B9·B11', () => {
-    const rows = rebarSummary(buildPier({ ...loadP1(), footingRebar: { sW: 150 } })).rows;
+  it('방향 (문서 기준, 승인 2026-10-26): B1–B4·B9·B12는 교각축(sAxis), B5–B8·B11은 교각축 직각(sPerp)', () => {
+    const rows = rebarSummary(buildPier({ ...loadP1(), footingRebar: { sPerp: 150 } })).rows;
     expect(rows.find((r) => r.name === 'B5')!.spacing).toBe('300');
     expect(rows.find((r) => r.name === 'B5')!.basis).toBe('input');
-    expect(rows.find((r) => r.name === 'B12')!.spacing).toBe('1200 (8s)');
-    expect(rows.find((r) => r.name === 'B11')!.basis).toBe('default');
+    expect(rows.find((r) => r.name === 'B11')!.spacing).toBe('1200 (8s)');
+    expect(rows.find((r) => r.name === 'B12')!.basis).toBe('default');
     expect(rows.find((r) => r.name === 'B1')!.basis).toBe('default');
 
-    const rowsL = rebarSummary(buildPier({ ...loadP1(), footingRebar: { sL: 150 } })).rows;
-    expect(rowsL.find((r) => r.name === 'B1')!.spacing).toBe('300');
-    expect(rowsL.find((r) => r.name === 'B9')!.spacing).toBe('600 (4s)');
-    expect(rowsL.find((r) => r.name === 'B11')!.spacing).toBe('1200 (8s)');
-    expect(rowsL.find((r) => r.name === 'B5')!.basis).toBe('default');
+    const rowsAxis = rebarSummary(buildPier({ ...loadP1(), footingRebar: { sAxis: 150 } })).rows;
+    expect(rowsAxis.find((r) => r.name === 'B9')!.spacing).toBe('600 (4s)');
+    expect(rowsAxis.find((r) => r.name === 'B12')!.spacing).toBe('1200 (8s)');
+    expect(rowsAxis.find((r) => r.name === 'B5')!.basis).toBe('default');
   });
 
   it('k 배수: k 4 → 간격 500, 개수 60 / 47 (문서 4s 값)', () => {