fix(bearing): C4·C5 are the 교축 distances from the bearing to the block edges (승인 2026-10-26)

- bearingEdgeDistances now reads the block geometry: 분리 1200 blocks are
  centred on the bearing (600 / 600); 일체 uses the pair's 2500 block (outer
  margins 601, within the 5 mm tolerance of 600).
- The plan labels C4 and C5 from these values; the coping-edge definition is removed.

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

tests/bearing-layout.test.ts

@@ -5,6 +5,8 @@ import { validatePier } from '../src/core/validate';
 import type { Issue } from '../src/core/types';
 import { loadP1 } from './helpers';
 
+const integrated = buildPier({ ...loadP1(), bearingLayout: '일체' });
+
 const model = buildPier(loadP1());
 
 function block(no: number, row: '전열' | '후열', s: number): BlockModel {
@@ -12,14 +14,20 @@ function block(no: number, row: '전열' | '후열', s: number): BlockModel {
 }
 
 describe('받침 배치 규칙 (승인 2026-10-26)', () => {
-  it('C4 and C5 from the model: distances from the two coping edges across the width (교각축 직각), P1 front 852 / 2248', () => {
+  it('C4 and C5 from the block edges along the 교축: 분리 blocks are centred, so both are 600', () => {
     const d = bearingEdgeDistances(model);
     expect(d).toHaveLength(10);
-    const first = d.find((x) => x.no === 1 && x.row === '전열')!;
-    expect(first.leftMm).toBeCloseTo(852, 0);
-    expect(first.rightMm).toBeCloseTo(2248, 0);
-    // the two edges are one coping width (3100) apart
-    for (const x of d) expect(x.leftMm + x.rightMm).toBeCloseTo(3100, 6);
+    for (const x of d) {
+      expect(x.leftMm).toBeCloseTo(600, 0);
+      expect(x.rightMm).toBeCloseTo(600, 0);
+    }
+  });
+
+  it('일체: the outer margins stay 600 (C4 of the front bearing, C5 of the back bearing)', () => {
+    const d = bearingEdgeDistances(integrated);
+    // The 2500 block is centred on the pair midpoint, so the outer margins are 601 (within the 5 mm drawing tolerance of 600).
+    expect(d.find((x) => x.no === 1 && x.row === '전열')!.leftMm).toBeCloseTo(600, -1);
+    expect(d.find((x) => x.no === 6 && x.row === '후열')!.rightMm).toBeCloseTo(600, -1);
   });
 
   it('the front and back bearings of one number are about 85 mm apart on P1, so 일체 is allowed', () => {

tests/bearing-plan-svg.test.ts

@@ -7,10 +7,10 @@ const separate = buildPier(loadP1());
 const integrated = buildPier({ ...loadP1(), bearingLayout: '일체' });
 
 describe('교량받침 상세 평면 (승인 2026-10-26)', () => {
-  it('shows C4 and C5 across the coping width (P1 front 852 / 2248)', () => {
+  it('shows C4 and C5 from the bearing to the block edges along the 교축 (600 each)', () => {
     const svg = bearingPlanSvg(separate, 0);
-    expect(svg).toContain('C4 852');
-    expect(svg).toContain('C5 950');
+    expect(svg).toContain('C4 600');
+    expect(svg).toContain('C5 600');
   });
 
   it('분리 draws two 1200 outlines; 일체 draws one 2500 outline (block outline only)', () => {