fix(rebar): 측면 수평 C12 = 상단 · C13 = 하단 변화구간 (엑셀 Pier B357–G358)

T형과 다주형 모두 엑셀 Pier 시트 철근표(C12 상단, C13 하단(변화구간))에 맞춰
측면 수평철근 번호를 서로 바꾼다 (사용자 결정 2026-11-06).
- 경사 하면에서 끊기는 아래 단 → C13, 끝면까지 가는 위 단 → C12
- 철근표 위치·비고 문구, 3D, 다주형 생성기가 같은 원천(sideRows)을 따른다
- C14 높이 순서를 유지하도록 측면 단을 아래(C13) → 위(C12) 순서로 넘김
- 테스트 기대값의 번호를 교환 (P1: C12 2단 8개, C13 5단 20개)

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

tests/coping-geom.test.ts

@@ -61,7 +61,7 @@ describe('① 코핑 끝단 높이 h1 · 테이퍼 높이 h2 · Level 폭 (1단
   });
 });
 
-describe('C12 in the taper band (h2), C13 in the end band (h1)', () => {
+describe('C13 in the taper band (h2), C12 in the end band (h1)', () => {
   const bands = (input: Parameters<typeof buildPier>[0]) => {
     const m = buildPier(input);
     const lv = sideRowLevels(m.levelBottom, m.endBottom);
@@ -73,13 +73,13 @@ describe('C12 in the taper band (h2), C13 in the end band (h1)', () => {
     ['h1 800', { copingH1Mm: 800 }],
     ['h1 1200', { copingH1Mm: 1200 }],
     ['h2 1800', { copingH2Mm: 1800 }],
-  ])('%s: every C12 row is in the taper band and every C13 row in the end band', (_name, change) => {
+  ])('%s: every C13 row is in the taper band and every C12 row in the end band', (_name, change) => {
     const { m, rows } = bands({ ...loadP1(), ...change });
-    for (const z of rows.c12) {
+    for (const z of rows.c13) {
       expect(z).toBeGreaterThanOrEqual(m.levelBottom - 1e-9);
       expect(z).toBeLessThan(m.endBottom + SIDE_COVER_M);
     }
-    for (const z of rows.c13) {
+    for (const z of rows.c12) {
       expect(z).toBeGreaterThanOrEqual(m.endBottom + SIDE_COVER_M - 1e-9);
       expect(z).toBeLessThanOrEqual(m.copingRefTop);
     }
@@ -92,23 +92,23 @@ describe('side-row grid (250, 상면 여유 400, 격자 연속)', () => {
     const lv = sideRowLevels(m.levelBottom, m.endBottom, m.copingRefTop);
     return { m, rows: sideRows(lv.zBottom, lv.zBreak, lv.zTop) };
   };
-  it('P1: 5 C12 rows and 2 C13 rows, the top row at or below top − 0.4', () => {
+  it('P1: 5 C13 rows and 2 C12 rows, the top row at or below top − 0.4', () => {
     const { m, rows } = rowsFor(loadP1());
-    expect(rows.c12).toEqual([41.288, 41.538, 41.788, 42.038, 42.288]);
-    expect(rows.c13).toEqual([42.538, 42.788]);
-    expect(Math.max(...rows.c13)).toBeLessThanOrEqual(m.copingRefTop - 0.4 + 1e-9);
+    expect(rows.c13).toEqual([41.288, 41.538, 41.788, 42.038, 42.288]);
+    expect(rows.c12).toEqual([42.538, 42.788]);
+    expect(Math.max(...rows.c12)).toBeLessThanOrEqual(m.copingRefTop - 0.4 + 1e-9);
   });
-  it('taper h2 = 3000: C12 from 39.788 to 42.288 (11 rows), C13 2 rows, no row lost to a fixed count', () => {
+  it('taper h2 = 3000: C13 from 39.788 to 42.288 (11 rows), C12 2 rows, no row lost to a fixed count', () => {
     const { rows } = rowsFor({ ...loadP1(), copingH2Mm: 3000 });
-    expect(rows.c12.length).toBe(11);
-    expect(rows.c12[0]).toBeCloseTo(39.788, 3);
-    expect(rows.c13).toEqual([42.538, 42.788]);
+    expect(rows.c13.length).toBe(11);
+    expect(rows.c13[0]).toBeCloseTo(39.788, 3);
+    expect(rows.c12).toEqual([42.538, 42.788]);
   });
-  it('the C13 first row is the last C12 row plus the pitch (the grid is continuous)', () => {
+  it('the C12 first row is the last C13 row plus the pitch (the grid is continuous)', () => {
     for (const h2 of [1000, 1500, 1750, 2000, 3000]) {
       const { rows } = rowsFor({ ...loadP1(), copingH2Mm: h2 });
-      if (rows.c12.length && rows.c13.length) {
-        expect(rows.c13[0] - rows.c12[rows.c12.length - 1]).toBeCloseTo(0.25, 6);
+      if (rows.c13.length && rows.c12.length) {
+        expect(rows.c12[0] - rows.c13[rows.c13.length - 1]).toBeCloseTo(0.25, 6);
       }
     }
   });