feat(abut-rebar): ③ 교대 접속슬래브 3D 철근 (R1–R8)

- 접속슬래브 배근 경로를 교대 3D 철근에 추가 (선택 · 색 기준 공통)
- 콘크리트 안 검사에 접속슬래브 포함: 모든 교대 철근 (P10 다웰 포함) 밖으로 나간 점 없음

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

verify/dump/abut-rebar-outside.dump.ts

@@ -9,7 +9,8 @@ import { buildAbut } from '../../src/core/abut/geometry';
 import { parseAbutments, toAbutInput } from '../../src/core/abut/parse';
 import { buildMembers } from '../../src/core/abut/members';
 import { buildWings } from '../../src/core/abut/wings';
-import { resolveSlab } from '../../src/core/abut/slab';
+import { resolveSlab, slabGradePct, slabSection } from '../../src/core/abut/slab';
+import { abutSlabGeom, abutSlabRebar } from '../../src/core/abut/rebar/slab';
 import { abutFootingGeom, abutFootingRebar } from '../../src/core/abut/rebar/footing';
 import { skewAngle } from '../../src/core/abut/rebar/skew-layout';
 import { abutWallGeom, abutWallRebar } from '../../src/core/abut/rebar/wall';
@@ -39,12 +40,14 @@ it('dump 콘크리트 밖 철근', () => {
   const para = abutParapetRebar(pg, wall);
   const seats = members.wallSegments.map((sg) => ({ from: sg.sFrom * 1000, to: sg.sTo * 1000, z: (sg.seatEl - members.footingBottomEl!) * 1000 }));
   const wingR = wings.map((w) => abutWingRebar(abutWingGeom(model, members, w, footing.z.B68, seats, k)));
-  const rebar = buildAbutRebar3D(fg, footing, k, members.shape.footingBackM, members.footingBottomEl!, wall, para, wingR);
+  const grade = slabGradePct(slab, model.wing?.slopePct ?? 0);
+  const slabG = abutSlabGeom(slab.form, abutPlanOutline(model, members, wings, slab).slab, slabSection(slab, grade, members.shape), { startEl: members.parapetTopStartEl, endEl: members.parapetTopEndEl, L: model.length, bottomEl: members.footingBottomEl! }, [300, 300], slab.lengthMm, grade);
+  const rebar = buildAbutRebar3D(fg, footing, k, members.shape.footingBackM, members.footingBottomEl!, wall, para, wingR, abutSlabRebar(slabG));
   const group = buildAbutGroup(model, members, wings);
   group.updateMatrixWorld(true);
   const solids: THREE.Mesh[] = [];
   group.traverse((o) => {
-    if (o instanceof THREE.Mesh && !['ground', 'slab', 'blinding', 'piles'].some((n) => o.parent?.name === n || o.name === n)) solids.push(o);
+    if (o instanceof THREE.Mesh && !['ground', 'blinding', 'piles'].some((n) => o.parent?.name === n || o.name === n)) solids.push(o);
   });
   const ray = new THREE.Raycaster();
   const inside = (p: THREE.Vector3) =>