feat(core,view): per-row pile counts 열별 본수 (plan C4)

- A 열 is one row across the footing width; each has its own count along the
  length. Default floor((L − 1400) / 2250) + 1 per 열, as in spec §4.6.
- Counts are validated: one per 열, whole numbers 2–30. Spacing below the
  2250 mm minimum is shown as a warning, not refused (the plan's 6본 → 5@1800
  example).
- PierInput gains an optional pileRows; absent means the defaults, so existing
  files and the P1 results are unchanged.
- Change tracking compares arrays by value; 열별 본수 can be reverted and
  copied (copy item off by default).
- The footing card has −/+ per 열 with spacing, total, and the display string.
- Tests: defaults 4열 × 5본 = 20 and the 1단계 text; 6본 → 5@1800; limits;
  model-level 21 piles.
- Not verified in a browser.

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

src/core/copy.ts

@@ -5,7 +5,7 @@ import type { PierInput } from './types';
  * 속성 복사 (spec §9 · plan C7). Copies chosen attributes from one pier to others.
  * Values the spec never copies (coordinates, IP, elevations, names) are not in any item, so they cannot be copied.
  */
-export type CopyItem = 'coping-width' | 'coping-length' | 'pile-length';
+export type CopyItem = 'coping-width' | 'coping-length' | 'pile-length' | 'pile-rows';
 
 interface ItemRule {
   label: string;
@@ -20,14 +20,15 @@ export const COPY_ITEMS: Record<CopyItem, ItemRule> = {
   'coping-width': { label: '코핑 폭', keys: ['copingWidthMm'], defaultOn: true, pileItem: false },
   'coping-length': { label: '코핑 길이 L', keys: ['copingLengthMm'], defaultOn: false, pileItem: false },
   'pile-length': { label: '말뚝 길이', keys: ['pileLengthMm'], defaultOn: false, pileItem: true },
+  'pile-rows': { label: '열별 본수', keys: ['pileRows'], defaultOn: false, pileItem: true },
 };
 
 export const DEFAULT_COPY_ITEMS: CopyItem[] = (Object.keys(COPY_ITEMS) as CopyItem[]).filter((k) => COPY_ITEMS[k].defaultOn);
 
 export interface CopyChange {
   key: EditableKey;
-  from: number;
-  to: number;
+  from: unknown;
+  to: unknown;
 }
 
 export interface CopyPlan {
@@ -47,7 +48,7 @@ export function planCopy(source: PierInput, target: PierInput, items: CopyItem[]
       continue;
     }
     for (const key of rule.keys) {
-      if (source[key] === target[key]) continue;
+      if (JSON.stringify(source[key]) === JSON.stringify(target[key])) continue;
       changes.push({ key, from: target[key], to: source[key] });
     }
   }
@@ -56,7 +57,7 @@ export function planCopy(source: PierInput, target: PierInput, items: CopyItem[]
 
 /** Applies a plan to a target input. Only the planned keys change. */
 export function applyCopy(target: PierInput, plan: CopyPlan): PierInput {
-  const next = { ...target };
+  const next: Record<string, unknown> = { ...target };
   for (const c of plan.changes) next[c.key] = c.to;
-  return next;
+  return next as unknown as PierInput;
 }