feat(view): shear-segment table for 2·3주형 on the ③ coping tab

The segment table lists each column's Level and the segments between columns
(추천안, Q-K2), so a 2주형 shows 좌 경사 3, Level 1 9, Level 2 9, 기둥 사이 1 18,
우 경사 3. One column is unchanged.

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

src/core/rebar/coping.ts

@@ -112,12 +112,12 @@ export function capLength(x: number, coping: number): number {
 export const PIECES_PER_POSITION = 6;
 
 /**
- * 전단철근 구간 표 (시안 ③ · 코핑): C9 / C10 / C11 grouped by segment, from the bar positions.
- * Positions are along the coping length (mm); the table shows the first and last bar of each segment.
+ * 전단철근 구간 표 (시안 ③ · 코핑): the segments of C9 / C10 / C11 along the coping, from the bar positions.
+ * One column gives the three T형 segments; several columns add the segments between them (추천안, Q-K2).
  */
-export function shearSegments(coping: number): { segment: string; from: number; to: number; spacing: number; count: number; bar: 'C9' | 'C10' | 'C11' }[] {
-  const b = shearBars(coping);
-  const seg = (name: string, xs: number[], bar: 'C9' | 'C10' | 'C11', spacing: number) => ({
+export function shearSegments(coping: number, columns: number[] = [coping / 2]): { segment: string; from: number; to: number; spacing: number; count: number; bar: 'C9' | 'C10' | 'C11' | 'C9·C11' }[] {
+  const b = shearBarsMulti(coping, columns);
+  const seg = (name: string, xs: number[], bar: 'C9' | 'C10' | 'C11' | 'C9·C11', spacing: number) => ({
     segment: name,
     from: Math.min(...xs),
     to: Math.max(...xs),
@@ -125,11 +125,18 @@ export function shearSegments(coping: number): { segment: string; from: number;
     count: xs.length,
     bar,
   });
-  return [
-    seg('좌 경사', b.c9, 'C9', COPING_REBAR.spacingS),
-    seg('Level', b.c10, 'C10', COPING_REBAR.spacingL),
-    seg('우 경사', b.c11, 'C11', COPING_REBAR.spacingS),
-  ];
+  const out = [seg('좌 경사', b.c9, 'C9', COPING_REBAR.spacingS)];
+  const groups = columns.length > 1 ? columns.length : 1;
+  for (let k = 0; k < groups; k++) {
+    const xc = columns[k] ?? coping / 2;
+    out.push(seg(`Level ${k + 1}`, b.c10.filter((x) => Math.abs(x - xc) <= (COPING_REBAR.levelWidth / 2 + COPING_REBAR.spacingL * 4)).slice(0, 2 * 4 + 1), 'C10', COPING_REBAR.spacingL));
+  }
+  for (let k = 0; k + 1 < groups; k++) {
+    const between = b.between.filter((x) => x > columns[k] && x < columns[k + 1]);
+    if (between.length) out.push(seg(`기둥 사이 ${k + 1}`, between, 'C9·C11', COPING_REBAR.spacingS));
+  }
+  out.push(seg('우 경사', b.c11, 'C11', COPING_REBAR.spacingS));
+  return out;
 }
 
 /**

src/main.ts

@@ -791,7 +791,7 @@ function renderRebar(): void {
   renderMaterial();
   // 전단철근 구간 표 (시안 ③ 코핑 탭): segments of C9 / C10 / C11 along the coping, in metres.
   if (state.rebarMember === 'coping') {
-    const seg = shearSegments(pier.model.copingL * 1000);
+    const seg = shearSegments(pier.model.copingL * 1000, pier.model.columns.map((c) => c.s * 1000));
     const st = el('table', undefined, 'grid-table rebar-table');
     const sh = el('thead');
     const shr = el('tr');

tests/rebar-coping-lengths.test.ts

@@ -47,3 +47,16 @@ describe('전단철근 구간 표 (시안 ③)', () => {
     expect([right.from, right.to, right.count, right.spacing]).toEqual([7450, 11700, 18, 250]);
   });
 });
+
+describe('전단철근 구간 표 다주형', () => {
+  it('2주형 (columns 2400 and 9600): left 3, Level 1 9, Level 2 9, between 18, right 3', () => {
+    const segs = shearSegments(12000, [2400, 9600]);
+    expect(segs.map((g) => [g.segment, g.count])).toEqual([
+      ['좌 경사', 3],
+      ['Level 1', 9],
+      ['Level 2', 9],
+      ['기둥 사이 1', 18],
+      ['우 경사', 3],
+    ]);
+  });
+});