feat: 판매대장 크기 필터를 봉투/음식물/폐기물 카테고리별 그룹으로

- 크기 드롭다운을 카테고리별 optgroup(봉투(일반용)/음식물/폐기물 등)으로 묶음
- 선택값을 '카테고리|크기'(예: general|3L)로 바꿔 카테고리+크기 조합 필터링
- 엑셀저장에도 size 파라미터 반영(기존 누락 수정)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/Views/admin/sales_report/sales_ledger.php

@@ -41,6 +41,9 @@ $exportParams = [
 if ($cats !== []) {
     $exportParams['cat'] = $cats;
 }
+if (($size ?? '') !== '') {
+    $exportParams['size'] = $size;
+}
 $excelUrl = mgmt_url('reports/sales-ledger?' . http_build_query($exportParams));
 ?>
 <?= view('components/print_header', [
@@ -117,10 +120,15 @@ $excelUrl = mgmt_url('reports/sales-ledger?' . http_build_query($exportParams));
         <?php endforeach; ?>
         <span class="inline-flex items-center gap-1 ml-2 pl-3 border-l border-gray-200">
           <span class="text-xs text-gray-600">크기</span>
-          <select name="size" class="border border-gray-300 rounded px-2 py-1 text-sm">
+          <select name="size" class="border border-gray-300 rounded px-2 py-1 text-sm min-w-[10rem]">
             <option value="">전체</option>
-            <?php foreach (($sizeOptions ?? []) as $sz): ?>
-            <option value="<?= esc($sz, 'attr') ?>" <?= ($size ?? '') === $sz ? 'selected' : '' ?>><?= esc($sz) ?></option>
+            <?php foreach (($sizeGroups ?? []) as $g): ?>
+            <optgroup label="<?= esc($g['label'], 'attr') ?>">
+              <?php foreach (($g['sizes'] ?? []) as $sz): ?>
+                <?php $val = $g['key'] . '|' . $sz; ?>
+                <option value="<?= esc($val, 'attr') ?>" <?= ($size ?? '') === $val ? 'selected' : '' ?>><?= esc($sz) ?></option>
+              <?php endforeach; ?>
+            </optgroup>
             <?php endforeach; ?>
           </select>
         </span>