feat(rebar): B10-2 최하단 단 삭제, 측면 B2 다리선 강조 (모서리 연결)

- B10-2 최하단(z = c_b)도 하면 1단 B2·B4와 같은 높이에서 간섭하므로 삭제 (승인 2026-10-26)
- B10-2: 18 → 16본 (8단 × 2면). 표와 3D가 같은 규칙
- 단면 그림의 측면 B2 다리선을 굵은 주황 실선으로 그려 모서리 연결을 드러냄
- 테스트 기대값 갱신 (B10-2 16)

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

tests/rebar-footing.test.ts

@@ -51,11 +51,11 @@ describe('확대기초 철근 (확대기초철근 (1).md, plan C5)', () => {
     expect(bars.find((b) => b.name === 'B6')!.length).toBeCloseTo(11396, 0);
   });
 
-  it('B10-1 16 bars ≈ 10748 (lowest level removed), B10-2 18 bars ≈ 8494', () => {
+  it('B10-1 16 bars ≈ 10748 (lowest level removed), B10-2 16 bars ≈ 8494', () => {
     const [b101, b102] = sideBars(L, W, H);
     expect(b101.count).toBe(16);
     expect(b101.length).toBeCloseTo(10748, 0);
-    expect(b102.count).toBe(18);
+    expect(b102.count).toBe(16);
     expect(b102.length).toBeCloseTo(8494, 0);
   });
 

tests/rebar-summary.test.ts

@@ -35,11 +35,11 @@ describe('③ 철근표 요약 (P1)', () => {
     expect(count('P6')).toBe(32);
   });
 
-  it('footing: B1–B4 31 each, B5–B8 40 each, B10-1 16, B10-2 18, B11 30, B12 24 (k = 8)', () => {
+  it('footing: B1–B4 31 each, B5–B8 40 each, B10-1 16, B10-2 16, B11 30, B12 24 (k = 8)', () => {
     for (const n of ['B1', 'B2', 'B3', 'B4']) expect(count(n)).toBe(31);
     for (const n of ['B5', 'B6', 'B7', 'B8']) expect(count(n)).toBe(40);
     expect(count('B10-1')).toBe(16);
-    expect(count('B10-2')).toBe(18);
+    expect(count('B10-2')).toBe(16);
     expect(count('B11')).toBe(30);
     expect(count('B12')).toBe(24);
   });

tests/rebar3d.test.ts

@@ -108,9 +108,9 @@ describe('확대기초 B9 · B10 · B11 · B12 in 3D (확대기초철근 (1).md
     expect(rb.byName.get('B9')!.length).toBe(306 * 3);
   });
 
-  it('B10-1: 16 (8 levels × 2 faces, lowest removed); B10-2: 18 (9 levels × 2 faces); B11 30, B12 24 at k = 8 — one tube per bar (bends rounded, 수정 2026-10-23)', () => {
+  it('B10-1: 16 (8 levels × 2 faces, lowest removed); B10-2: 16 (8 levels × 2 faces, lowest removed); B11 30, B12 24 at k = 8 — one tube per bar (bends rounded, 수정 2026-10-23)', () => {
     expect(rb.byName.get('B10-1')!.length).toBe(16);
-    expect(rb.byName.get('B10-2')!.length).toBe(18);
+    expect(rb.byName.get('B10-2')!.length).toBe(16);
     expect(rb.byName.get('B11')!.length).toBe(30);
     expect(rb.byName.get('B12')!.length).toBe(24);
   });