feat(shape): 교좌면 EL로 받침별 코핑 상면 계단을 만든다 (W10은 정보)

입력 교좌면 EL이 있으면 그 받침 구간의 코핑 상면 = 교좌면 EL (없으면 z − h1 / z − h2).
받침블럭 바닥과 코핑 상면이 항상 맞아 블럭이 뜨거나 묻히지 않는다. seatCalc는 기울기 계산값으로 남겨
W10 비교 기준으로 쓰고, W10은 경고(W)에서 정보(I)로 바꾼다.

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

src/core/geometry.ts

@@ -337,13 +337,15 @@ export function buildPier(input: PierInput, ctx: PierContext = {}): PierModel {
     bounds.push((frontPlaced[k].g + frontPlaced[k + 1].g) / 2);
   }
   bounds.push(L);
-  const segments: Segment[] = frontPlaced.map((b, k) => ({ s0: bounds[k], s1: bounds[k + 1], top: b.z - h1 }));
+  // 교좌면 EL per bearing (2026-11-10): when given, it is the coping top of that bearing's step; otherwise z − h1 (z − h2 behind).
+  const seatOf = new Map(input.bearings.map((r) => [r.no, r.seatEl]));
+  const segments: Segment[] = frontPlaced.map((b, k) => ({ s0: bounds[k], s1: bounds[k + 1], top: seatOf.get(b.no) ?? b.z - h1 }));
 
   // Lateral step (spec §4.3, Q1·Q2 추천안): front and back tops differ by 5 mm or more in some segment.
   const backSegments: Segment[] = backPlaced.map((b,k) => ({
     s0: unequalRows ? (k === 0 ? 0 : (backPlaced[k-1].g+b.g)/2) : segments[k].s0,
     s1: unequalRows ? (k === backPlaced.length-1 ? L : (b.g+backPlaced[k+1].g)/2) : segments[k].s1,
-    top: b.z-h2,
+    top: seatOf.get(b.no) ?? b.z-h2,
   }));
   const stepBounds = [...new Set([0,L,...segments.slice(1).map(s=>s.s0),...backSegments.slice(1).map(s=>s.s0)])].sort((a,b)=>a-b);
   const stepSamples = stepBounds.slice(1).map((end,k)=>(stepBounds[k]+end)/2);
@@ -478,9 +480,9 @@ export function buildPier(input: PierInput, ctx: PierContext = {}): PierModel {
   };
   const dropOf = (no: number) => soles.get(no)!.dropMm / 1000;
   // 교좌면 EL (2026-11-03): when the input gives it, the block bottom is that EL; otherwise the 두부보 상면 slope.
-  const seatOf = new Map(input.bearings.map((r) => [r.no, r.seatEl]));
+  // seatCalc stays the slope value (z − h1, z − h2) as the W10 reference.
   frontPlaced.forEach((b) => {
-    const seatCalc = segmentTop(segments, b.g);
+    const seatCalc = b.z - h1;
     const bottom = seatOf.get(b.no) ?? seatCalc;
     const skew = skewOf(b.no, b.k), drop = dropOf(b.no);
     blocks.push({ no: b.no, row: '전열', k: b.k, s: b.s, g: b.g, n: b.n, bottom, top: b.z - DIM.padThickness - drop, padTop: b.z - drop, rowSkewDeg: skew, plan: planOf(b.no, b.k, skew), seatCalc });