feat(view): 교각 목록 and bulk line in the ③ left column (시안 ③)

The ③ screen had no pier list. The left column now has the 교각 목록 with
checkboxes and a 배근 status (계산됨 / 오류), the 선택 n기 line with 속성 복사…,
then 부재 · 배근 타입. The checks are shared with ① and ②.

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

src/main.ts

@@ -252,7 +252,7 @@ function renderPierList(): void {
 }
 
 /** Rows of the pier list. ① shows the type and warnings; ② shows the count of changes from the defaults. */
-function renderPierRows(list: HTMLUListElement, mode: 'shape' | 'plan'): void {
+function renderPierRows(list: HTMLUListElement, mode: 'shape' | 'plan' | 'rebar'): void {
   list.replaceChildren();
   const visible = state.piers.filter((p) => state.filter === 'all' || p.input.type === state.filter);
   for (const pier of visible) {
@@ -276,6 +276,8 @@ function renderPierRows(list: HTMLUListElement, mode: 'shape' | 'plan'): void {
     });
     const badge = mode === 'plan'
       ? el('span', `변경 ${overrideKeys(pier).length}`, 'badge')
+      : mode === 'rebar'
+        ? (pier.model ? el('span', '계산됨', 'badge') : el('span', '오류', 'badge error'))
       : pier.model
         ? el('span', `${pier.input.type}${pier.issues.some((i) => i.level !== 'I') ? ' · 경고' : ''}`, 'badge')
         : el('span', '오류', 'badge error');
@@ -701,6 +703,11 @@ const REBAR_MEMBERS: { id: RebarRow['member']; label: string }[] = [
 
 function renderRebar(): void {
   const pier = activePier();
+  // 교각 목록 with the 배근 status (시안 ③). The checks are the same as in ① and ②.
+  renderPierRows($<HTMLUListElement>('rebar-pier-items'), 'rebar');
+  const checked = state.piers.filter((p) => p.checked).length;
+  $('rebar-bulk-count').textContent = `선택 ${checked}기`;
+  $<HTMLButtonElement>('rebar-bulk-copy').disabled = !pier;
   const tabs = $<HTMLUListElement>('rebar-tabs');
   tabs.replaceChildren();
   for (const m of REBAR_MEMBERS) {
@@ -1247,6 +1254,7 @@ $<HTMLButtonElement>('dlg-apply').addEventListener('click', applyImport);
 $<HTMLButtonElement>('regen').addEventListener('click', regenerateChecked);
 $<HTMLButtonElement>('bulk-regen').addEventListener('click', regenerateChecked);
 $<HTMLButtonElement>('bulk-copy').addEventListener('click', openCopyDialog);
+$<HTMLButtonElement>('rebar-bulk-copy').addEventListener('click', openCopyDialog);
 $<HTMLButtonElement>('nav-shape').addEventListener('click', () => setStage('shape'));
 $<HTMLButtonElement>('nav-plan').addEventListener('click', () => setStage('plan'));
 $<HTMLButtonElement>('nav-rebar').addEventListener('click', () => setStage('rebar'));