feat(core,view): footing rebar B1–B12 (plan C5) and the ③ rebar screen v1

- Footing (확대기초철근 (1).md): grid counts from W and L, layer heights,
  B1–B4 and B5–B8 counts and lengths (B2 13646, B6 11396), B10-1/B10-2,
  B11 (60) and B12 (47) with their lengths. B9 is not computed yet.
- rebarSummary: one 철근표 per pier from the model (bearing, coping, column,
  footing), with alerts: RB-F08 (B2 needs a splice, Q-B6), RB-F09 (B9 not
  computed).
- ③ screen v1: stage nav button, member tabs (받침블럭 · 코핑 · 기둥 · 확대기초),
  rebar table with 번호 · 규격 · 개수 · 길이 · 비고, alert list, and the open
  questions (Q-B5, Q-B6, Q-C9). Drawings and the 강조 연동 are not in v1.
- Tests: footing values from the document; P1 summary totals; warnings.
- Not verified in a browser.

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

src/core/rebar/summary.ts

@@ -0,0 +1,98 @@
+import type { PierModel } from '../geometry';
+import { bearingBlockRebar, totals } from './bearing-block';
+import { bottomPiece, topBarLength, widthLayout } from './coping-main';
+import { shearBars, sideRows, C14_COUNTS, c14Total, STEP_BAR_COUNTS } from './coping';
+import { columnRebar, COLUMN_P1 } from './column';
+import { bottomBars, crossBars, sideBars, assemblyBars } from './footing';
+
+/** One line of a 철근표. length is null where the document gives no length yet. */
+export interface RebarRow {
+  member: 'bearing' | 'coping' | 'column' | 'footing';
+  name: string;
+  size: string;
+  count: number;
+  length: number | null;
+  note: string;
+}
+
+export interface RebarWarning {
+  code: string;
+  message: string;
+}
+
+/** 정척 L_bar (mm) from 확대기초철근.md §1.2. Bars longer than this need a splice. */
+export const STANDARD_BAR = 12000;
+
+/**
+ * 철근표 for one pier (③ screen v1): bearing blocks, coping, column, footing. Built from the generated model.
+ * Values come from the document rules in src/core/rebar/*. B9 (전단철근) is not computed yet.
+ */
+export function rebarSummary(model: PierModel): { rows: RebarRow[]; warnings: RebarWarning[] } {
+  const rows: RebarRow[] = [];
+  const warnings: RebarWarning[] = [];
+  const L = model.copingL * 1000;
+  const B = model.copingB * 1000;
+
+  // Bearing blocks (§6.3 · plan C2)
+  const blk = totals(bearingBlockRebar(model));
+  rows.push({ member: 'bearing', name: 'S1', size: 'H19', count: blk.S1, length: 2500, note: '블럭 배치 분리, 블럭당 8본' });
+  rows.push({ member: 'bearing', name: 'S2', size: 'H19', count: blk.S2, length: 2500, note: '블럭 배치 분리, 블럭당 8본' });
+
+  // Coping (코핑철근.md §5–§8)
+  const width = widthLayout(B);
+  const perRow = width.count / 2; // cycle split, 12 per row
+  // C1–C3 and C4–C6 are the same three top rows (row 1, 2, 3), one set per cycle.
+  for (const [name, k] of [['C1', 1], ['C2', 2], ['C3', 3], ['C4', 1], ['C5', 2], ['C6', 3]] as const) {
+    rows.push({ member: 'coping', name, size: 'H29', count: perRow, length: topBarLength(L, k), note: '상면, 이음 무시' });
+  }
+  const bottom = bottomPiece();
+  rows.push({ member: 'coping', name: 'C7', size: 'H29', count: perRow, length: bottom.piece, note: '하면, 2조각 겹침이음' });
+  rows.push({ member: 'coping', name: 'C8', size: 'H29', count: perRow, length: bottom.piece, note: '하면, 2조각 겹침이음' });
+  const shear = shearBars(L);
+  rows.push({ member: 'coping', name: 'C9', size: 'H25', count: shear.c9.length, length: null, note: '전단 좌 @250' });
+  rows.push({ member: 'coping', name: 'C10', size: 'H25', count: shear.c10.length, length: null, note: '전단 Level @300' });
+  rows.push({ member: 'coping', name: 'C11', size: 'H25', count: shear.c11.length, length: null, note: '전단 우 @250' });
+  const side = sideRows(41.288, 42.538);
+  rows.push({ member: 'coping', name: 'C12', size: 'H25', count: side.c12.length, length: null, note: '측면, 경사 하면에서 끊김' });
+  rows.push({ member: 'coping', name: 'C13', size: 'H25', count: side.c13.length, length: null, note: '측면, 끝면까지' });
+  rows.push({ member: 'coping', name: 'C14', size: 'H19', count: c14Total(), length: null, note: `직각 수평 ${C14_COUNTS.upperLines * C14_COUNTS.upperPerLine}+${C14_COUNTS.lower.join('+')}` });
+  rows.push({ member: 'coping', name: 'C15', size: 'H19', count: STEP_BAR_COUNTS.C15, length: null, note: '계단부, 가장 높은 구간' });
+  rows.push({ member: 'coping', name: 'C16', size: 'H19', count: STEP_BAR_COUNTS.C16, length: null, note: '계단부, 3·4구간' });
+
+  // Column (기둥철근.md · plan C4), P1 defaults
+  const col = columnRebar(COLUMN_P1);
+  rows.push({ member: 'column', name: 'P1', size: 'S32', count: col.mainP1, length: null, note: '외측 r 875, 커플러로 이음' });
+  rows.push({ member: 'column', name: 'P2', size: 'S32', count: col.mainP2, length: null, note: '내측 r 843.2, 커플러로 이음' });
+  rows.push({ member: 'column', name: '커플러', size: 'L150 Ø60', count: col.couplers, length: 150, note: '@3000, P2 +150' });
+  rows.push({ member: 'column', name: 'P3', size: 'H19', count: col.p3Count, length: null, note: '일반 구간 띠철근 @300' });
+  rows.push({ member: 'column', name: 'P5', size: 'H19', count: col.p5Count, length: null, note: '단부 띠철근 @120' });
+  rows.push({ member: 'column', name: 'P4', size: 'H19', count: col.p4Count, length: col.p4SemicircleLength * 2, note: '확대기초 안, 반원 2개 (길이는 반원 2개 합) · B11 간섭 무시' });
+  rows.push({ member: 'column', name: 'P6', size: 'H16', count: col.p6Count, length: col.p6Length, note: '크로스타이, 8단 × 4' });
+
+  // Footing (확대기초철근 (1).md · plan C5). Only when the footing exists (not 현장타설말뚝).
+  const f = model.footings[0];
+  if (f) {
+    const Lf = f.length * 1000;
+    const Wf = f.width * 1000;
+    const Hf = (f.top - f.bottom) * 1000;
+    for (const b of bottomBars(Lf, Wf, Hf)) {
+      rows.push({ member: 'footing', name: b.name, size: b.size, count: b.count, length: b.length, note: '교각축' });
+      if (b.length > STANDARD_BAR) {
+        warnings.push({ code: 'RB-F08', message: `${b.name} 길이 ${Math.round(b.length)} mm가 정척 ${STANDARD_BAR} mm를 넘어 이음이 필요합니다 (Q-B6).` });
+      }
+    }
+    for (const b of crossBars(Lf, Wf, Hf)) {
+      rows.push({ member: 'footing', name: b.name, size: b.size, count: b.count, length: b.length, note: '교각축 직각' });
+      if (b.length > STANDARD_BAR) {
+        warnings.push({ code: 'RB-F08', message: `${b.name} 길이 ${Math.round(b.length)} mm가 정척 ${STANDARD_BAR} mm를 넘어 이음이 필요합니다 (Q-B6).` });
+      }
+    }
+    for (const b of sideBars(Lf, Wf)) rows.push({ member: 'footing', name: b.name, size: b.size, count: b.count, length: b.length, note: '측면 수평' });
+    for (const b of assemblyBars(Lf, Wf)) rows.push({ member: 'footing', name: b.name, size: b.size, count: b.count, length: b.length, note: '조립 수평' });
+    rows.push({ member: 'footing', name: 'B9', size: 'H16', count: 0, length: null, note: '전단철근 미계산' });
+    warnings.push({ code: 'RB-F09', message: 'B9 (전단철근)은 아직 계산하지 않았습니다.' });
+  } else {
+    warnings.push({ code: 'RB-F00', message: '현장타설말뚝은 확대기초가 없어 확대기초 철근을 만들지 않습니다.' });
+  }
+  return { rows, warnings };
+}