feat(plan): 형상계획 ②에서 선택한 교대만 3D와 카드에 표시

- 교대를 고르면 교각 장면·철근을 만들지 않고 선택한 교대만 그림. 교각을 고르면 교대를 숨김 (src/core/abut/visibility.ts)
- ①의 전체 보기와 ③·④는 기존 동작 유지
- 교대 선택 시 ②의 부재 목록·코핑 카드·속성 복사를 숨기고 교대 카드만 표시
- 카메라 맞춤은 보이는 객체만 포함
- 테스트 623건 통과, 타입 검사·빌드 통과. 브라우저 시각 확인은 미실시

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

src/main.ts

@@ -10,6 +10,7 @@ import { structureOrder } from './core/abut/order';
 import { ABUT_DETAIL_LABELS, abutInputRows, abutSummaryRows } from './core/abut/summary';
 import { applyAbutEdit, applyBearingEdit, applyShapeEdit, ABUT_EDIT_FIELDS, SHAPE_EDIT_FIELDS, restoreAbutDefault, setWingForm } from './core/abut/edit';
 import { ABUT_SHAPE_DEFAULT, resolveShape } from './core/abut/shape';
+import { abutShown, piersShown } from './core/abut/visibility';
 import { abutSectionSvg } from './view/abut-section-svg';
 import type { WingForm } from './core/abut/geometry';
 import { buildMembers } from './core/abut/members';
@@ -444,7 +445,7 @@ function fitToModels(position: THREE.Vector3, target: THREE.Vector3): { position
   const box = new THREE.Box3();
   const piersRoot = allPiers ? allPiers.piers : state.scene?.root;
   if (piersRoot) box.expandByObject(piersRoot);
-  for (const g of abutGroups) box.expandByObject(g);
+  for (const g of abutGroups) if (g.visible) box.expandByObject(g);
   if (box.isEmpty()) return { position, target };
   const sphere = box.getBoundingSphere(new THREE.Sphere());
   return fitCamera(position, target, sphere, camera.fov, camera.aspect);
@@ -496,6 +497,7 @@ function setupScene(): void {
         const model = buildAbut(toAbutInput(rec));
         const members = buildMembers(model, { bottomEl: rec.foundationBottomEl, pileLengthMm: rec.pileLengthMm }, rec.shape);
         const group = buildAbutGroup(model, members, buildWings(model, members, rec.wings), ref.pivot, rec.groundEl, groundModel?.terrainGrid);
+        group.visible = abutShown(state.stage, state.abutActive, rec.name);
         abutGroups.push(group);
         abutGroupByName.set(rec.name, group);
         world.add(group);
@@ -523,7 +525,8 @@ function setupScene(): void {
     return;
   }
   const pier = activePier();
-  if (pier?.model) {
+  // In ② an abutment selection draws the abutment alone, so the pier scene is not built (visibility.ts).
+  if (pier?.model && piersShown(state.stage, state.abutActive)) {
     rebar3d = buildRebar3D(pier.model, state.material, state.fckByMember);
     rebar3d.group.visible = state.stage === 'rebar';
     rebar3d.setColorMode(state.rebarColor);
@@ -573,6 +576,8 @@ function abutRow(rec: AbutRecord, mode: Stage = 'shape'): HTMLLIElement {
     state.abutActive = rec.name;
     state.abutEditOpen = false;
     setStatus(abutSummary(rec));
+    // Rebuilt first: the abutment and the camera frame are in the new scene (visibility.ts in ②).
+    setupScene();
     focusAbut(rec.name);
     renderAll();
   });
@@ -613,6 +618,8 @@ const ABUT_SLOTS = {
 function renderAbutEditor(): void {
   const rec = state.abutments.find((a) => a.name === state.abutActive);
   $<HTMLElement>('pier-info').hidden = Boolean(rec);
+  // ② hides the pier cards (부재 목록, 코핑 카드, 속성 복사) while an abutment is selected (style.css .abut-selected).
+  $<HTMLElement>('view-plan').classList.toggle('abut-selected', Boolean(rec));
   for (const slot of [ABUT_SLOTS.shape, ABUT_SLOTS.plan]) {
     const box = $<HTMLElement>(slot.root);
     box.hidden = !rec;
@@ -1426,9 +1433,11 @@ function wireRebarPicking(): void {
 function setStage(stage: Stage): void {
   // ① opens on 전체 보기 (default). The button is gone, so 전체 보기 returns each time ① is entered.
   if (stage === 'shape' && state.stage !== 'shape') state.allView = true;
+  const previous = state.stage;
   state.stage = stage;
   // Switching 전체 보기 on or off in ① needs the scene rebuilt for the new layout.
-  if ((allPiers !== null) !== multiSceneOn()) setupScene();
+  // Entering or leaving ② changes which objects are drawn (visibility.ts), so the scene is rebuilt then.
+  if ((allPiers !== null) !== multiSceneOn() || stage === 'plan' || previous === 'plan') setupScene();
   if (state.scene) setRebarView(state.scene, stage === 'rebar');
   $<HTMLElement>('view-shape').hidden = stage !== 'shape';
   $<HTMLElement>('view-plan').hidden = stage !== 'plan';