P2-03/04 봉투 단가 관리 CRUD + 이력 + 기간별 조회

- bag_price, bag_price_history 테이블 생성
- BagPriceModel, BagPriceHistoryModel
- BagPrice 컨트롤러 (목록/등록/수정/삭제/이력)
- 단가 변경 시 자동 이력 기록 (트랜잭션)
- 기간 필터 조회 (적용시작일/종료일)
- 봉투코드(O) 드롭다운 연동
- E2E 테스트 5개 전체 통과
- 스크린샷 2개 추가

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/Views/admin/bag_price/index.php

@@ -0,0 +1,60 @@
+<section class="border-b border-gray-300 p-2 shrink-0 bg-control-panel">
+  <div class="flex flex-wrap items-center justify-between gap-y-2">
+    <span class="text-sm font-bold text-gray-700">봉투 단가 관리</span>
+    <a href="<?= base_url('admin/bag-prices/create') ?>" class="bg-btn-search text-white px-4 py-1.5 rounded-sm flex items-center gap-1 text-sm shadow hover:opacity-90 transition border border-transparent">단가 등록</a>
+  </div>
+</section>
+<section class="p-2 bg-white border-b border-gray-200">
+  <form method="GET" action="<?= base_url('admin/bag-prices') ?>" class="flex flex-wrap items-center gap-2">
+    <label class="text-sm text-gray-600">적용시작일</label>
+    <input type="date" name="start_date" value="<?= esc($startDate ?? '') ?>" class="border border-gray-300 rounded px-2 py-1 text-sm"/>
+    <label class="text-sm text-gray-600">~</label>
+    <input type="date" name="end_date" value="<?= esc($endDate ?? '') ?>" class="border border-gray-300 rounded px-2 py-1 text-sm"/>
+    <button type="submit" class="bg-btn-search text-white px-4 py-1 rounded-sm text-sm">조회</button>
+    <a href="<?= base_url('admin/bag-prices') ?>" class="text-sm text-gray-500 hover:underline">초기화</a>
+  </form>
+</section>
+<div class="border border-gray-300 overflow-auto mt-2">
+  <table class="w-full data-table">
+    <thead>
+      <tr>
+        <th class="w-16">번호</th>
+        <th>봉투코드</th>
+        <th>봉투명</th>
+        <th>발주단가</th>
+        <th>도매가</th>
+        <th>소비자가</th>
+        <th>적용시작</th>
+        <th>적용종료</th>
+        <th class="w-20">상태</th>
+        <th class="w-36">작업</th>
+      </tr>
+    </thead>
+    <tbody class="text-right">
+      <?php foreach ($list as $row): ?>
+      <tr>
+        <td class="text-center"><?= esc($row->bp_idx) ?></td>
+        <td class="text-center font-mono"><?= esc($row->bp_bag_code) ?></td>
+        <td class="text-left pl-2"><?= esc($row->bp_bag_name) ?></td>
+        <td><?= number_format((float) $row->bp_order_price) ?></td>
+        <td><?= number_format((float) $row->bp_wholesale) ?></td>
+        <td><?= number_format((float) $row->bp_consumer) ?></td>
+        <td class="text-center"><?= esc($row->bp_start_date) ?></td>
+        <td class="text-center"><?= esc($row->bp_end_date ?? '현재') ?></td>
+        <td class="text-center"><?= (int) $row->bp_state === 1 ? '사용' : '미사용' ?></td>
+        <td class="text-center">
+          <a href="<?= base_url('admin/bag-prices/history/' . (int) $row->bp_idx) ?>" class="text-green-600 hover:underline text-sm mr-1">이력</a>
+          <a href="<?= base_url('admin/bag-prices/edit/' . (int) $row->bp_idx) ?>" class="text-blue-600 hover:underline text-sm mr-1">수정</a>
+          <form action="<?= base_url('admin/bag-prices/delete/' . (int) $row->bp_idx) ?>" method="POST" class="inline" onsubmit="return confirm('삭제하시겠습니까?');">
+            <?= csrf_field() ?>
+            <button type="submit" class="text-red-600 hover:underline text-sm">삭제</button>
+          </form>
+        </td>
+      </tr>
+      <?php endforeach; ?>
+      <?php if (empty($list)): ?>
+      <tr><td colspan="10" class="text-center text-gray-400 py-4">등록된 단가가 없습니다.</td></tr>
+      <?php endif; ?>
+    </tbody>
+  </table>
+</div>