feat(shape): 다주형 코핑 하면을 오목형으로 (Level D+200 · 오목 500 · 헌치 1500)

spec §3·§4.4(2026-11-06 개정)와 3주형형상배근.md §2.2(2주형 DWG 실측)를 따른다.
- 기둥 사이 하면: Level 끝에서 헌치 수평 1500 동안 500 올라가 평탄, 다음 기둥 앞에서 내려옴
  (이전 Level + 300, 헌치 300 × 300 대체)
- 다주형 Level 폭 기본값 = D + 200 (입력값이 있으면 입력 우선). T형은 2100 유지
- 오목 평탄부가 없으면 RB-M01 오류
- 3주형 테스트는 오목형이 성립하는 20 m 코핑으로 바꿈 (P1 길이 12 m는 RB-M01)
- 2주형 DWG 치수(L 24200, D 3000) 하면 꺾임점 테스트 추가

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

tests/validate-and-foundation.test.ts

@@ -82,27 +82,50 @@ describe('foundation types', () => {
     expect(m.piles[0].diameter).toBeCloseTo(0.6096, 6);
   });
 
-  it('2주형: underside between columns rises 300 above Level; column tops and T형 stay at Level', () => {
+  it('2주형: underside between columns is 오목형 (500 above Level); column tops and T형 stay at Level', () => {
     const t = buildPier(loadP1());
-    const raised = t.levelBottom + 0.3;
+    const raised = t.levelBottom + 0.5;
     expect(t.copingParts[0].profile.some(([, z]) => Math.abs(z - raised) < 1e-9)).toBe(false);
+    expect(t.copingGeom.levelWidth).toBe(2100);
 
     const two = buildPier({ ...loadP1(), type: '2주형', columnCount: 2 });
     expect(two.copingParts[0].profile.some(([, z]) => Math.abs(z - raised) < 1e-9)).toBe(true);
     const outlineLow = Math.min(...two.copingParts[0].profile.map(([, z]) => z));
     expect(outlineLow).toBeCloseTo(two.levelBottom, 9);
     expect(two.columns.every((c) => c.top === two.levelBottom)).toBe(true);
+    // Level width default for 2·3주형 = D + 200 (D 2000 when absent).
+    expect(two.copingGeom.levelWidth).toBe(2200);
   });
 
-  it('3주형 builds with two gaps of haunches', () => {
-    const m = buildPier({ ...loadP1(), type: '3주형', columnCount: 3 });
-    const raised = m.copingParts[0].profile.filter(([, z]) => Math.abs(z - (m.levelBottom + 0.3)) < 1e-9);
+  it('3주형 builds with two 오목형 spans', () => {
+    const m = buildPier({ ...loadP1(), type: '3주형', columnCount: 3, copingLengthMm: 20000 });
+    const raised = m.copingParts[0].profile.filter(([, z]) => Math.abs(z - (m.levelBottom + 0.5)) < 1e-9);
     expect(raised).toHaveLength(4);
   });
 
+  it('RB-M01: columns too close for two 1500 haunches → error', () => {
+    // P1 length 12.166 m as 3주형: columns L/5 · L/2 · 4L/5 are 3650 apart, minus Level 2200 = 1450 < 3000.
+    expect(() => buildPier({ ...loadP1(), type: '3주형', columnCount: 3 })).toThrow(/RB-M01/);
+  });
+
+  it('2주형 DWG dimensions (L 24200, D 3000): Level 3200, haunch 1500 rising 500 (3주형형상배근.md §2.2)', () => {
+    const m = buildPier({ ...loadP1(), type: '2주형', columnCount: 2, copingLengthMm: 24200, columnDiameterMm: 3000, copingH1Mm: 1500, copingH2Mm: 1500 });
+    expect(m.copingGeom.levelWidth).toBe(3200);
+    const profile = m.copingParts[0].profile;
+    const has = (x: number, z: number) => profile.some(([s, el]) => Math.abs(s - x) < 1e-9 && Math.abs(el - z) < 1e-9);
+    const [c1, c2] = m.columns.map((c) => c.s);
+    // Level ends at column ± 1.6, the haunch reaches Level + 0.5 another 1.5 inward, then the flat 오목 part.
+    expect(has(c1 + 1.6, m.levelBottom)).toBe(true);
+    expect(has(c1 + 3.1, m.levelBottom + 0.5)).toBe(true);
+    expect(has(c2 - 3.1, m.levelBottom + 0.5)).toBe(true);
+    expect(has(c2 - 1.6, m.levelBottom)).toBe(true);
+    // Ends: taper from the end height (h1 1500 below the top) down to Level.
+    expect(has(0, m.levelBottom + 1.5)).toBe(true);
+  });
+
   for (const type of ['2주형', '3주형'] as const) {
-    for (const dims of [{}, { copingLengthMm: 15000, copingH1Mm: 1200, copingH2Mm: 1000, levelWidthMm: 2400 }]) {
-      it(`${type}: raised spans and 300 × 300 haunches follow every column, dimensions ${JSON.stringify(dims)}`, () => {
+    for (const dims of [type === '2주형' ? {} : { copingLengthMm: 20000 }, { copingLengthMm: 22000, copingH1Mm: 1200, copingH2Mm: 1000, levelWidthMm: 2400 }]) {
+      it(`${type}: 오목형 spans and 1500 haunches follow every column, dimensions ${JSON.stringify(dims)}`, () => {
         const m = buildPier({ ...loadP1(), ...dims, type, columnCount: type === '2주형' ? 2 : 3 });
         const profile = m.copingParts[0].profile;
         const half = m.copingGeom.levelWidth / 2000;
@@ -115,8 +138,8 @@ describe('foundation types', () => {
         for (let i = 0; i < m.columns.length - 1; i++) {
           const left = m.columns[i].s + half;
           const right = m.columns[i + 1].s - half;
-          expect(has(left + 0.3, m.levelBottom + 0.3)).toBe(true);
-          expect(has(right - 0.3, m.levelBottom + 0.3)).toBe(true);
+          expect(has(left + 1.5, m.levelBottom + 0.5)).toBe(true);
+          expect(has(right - 1.5, m.levelBottom + 0.5)).toBe(true);
         }
         expect(Math.min(...profile.map(([, z]) => z))).toBeCloseTo(m.levelBottom, 9);
       });
@@ -171,10 +194,10 @@ describe('일체기초 (spec §4.6)', () => {
     expect(m.derived.pileLayout).toBe('7@2314 × 3@2250 = 32본');
   });
 
-  it('3주형 L 12000: three columns 3600 apart share one footing', () => {
-    const m = buildPier({ ...loadP1(), type: '3주형', columnCount: 3, copingLengthMm: 12000, foundationType: '직접기초' });
+  it('3주형 L 20000: three columns 6000 apart share one footing (outer distance + 10400)', () => {
+    const m = buildPier({ ...loadP1(), type: '3주형', columnCount: 3, copingLengthMm: 20000, foundationType: '직접기초' });
     expect(m.footings).toHaveLength(1);
-    expect(m.footings[0].length).toBeCloseTo(17.6, 6);
+    expect(m.footings[0].length).toBeCloseTo(22.4, 6);
   });
 
   it('2주형 with columns 18000 apart: separate footings of 10400', () => {