fix(view): round the lengths shown in the 재료표 and in the Excel rows to 0.1 mm

Single-piece lengths such as the B9 and C7 pieces showed long unrounded decimals (2128.1174619702915). They are rounded to
0.1 mm for display and in the Excel rows; the totals are unchanged.

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

src/core/rebar/quantity.ts

@@ -113,7 +113,7 @@ export function quantityRows(q: Quantity): (string | number)[][] {
   for (const g of q.groups) {
     for (const d of g.diameters) {
       for (const l of d.lines) {
-        out.push([`SD${g.grade}`, l.name, l.shape, l.size, l.count, l.length ?? '여러 길이', round(l.totalM), round(l.kgPerM, 3), round(l.kg)]);
+        out.push([`SD${g.grade}`, l.name, l.shape, l.size, l.count, l.length === null ? '여러 길이' : round(l.length), round(l.totalM), round(l.kgPerM, 3), round(l.kg)]);
       }
       out.push(['', `${d.size} 소계`, '', d.size, '', '', round(d.totalM), '', round(d.kg)]);
     }

src/main.ts

@@ -1058,7 +1058,7 @@ function quantityTargets(): Pier[] {
 
 /** Length cell of a 재료표 line: the length, or 여러 길이 with the pieces on hover. */
 function lengthCell(l: QuantityLine): HTMLTableCellElement {
-  if (l.length !== null) return el('td', String(l.length));
+  if (l.length !== null) return el('td', String(Math.round(l.length * 10) / 10));
   const cell = el('td', `여러 길이 (${l.pieces.length}종)`);
   cell.title = l.pieces.map((p) => `${Math.round(p.length)} × ${p.count}`).join(' · ');
   return cell;