feat(cupang): 쿠팡 밀크런 모듈 추가 (출고 달력/박스계산/입고센터)

- app/modules/cupang: router/db/store/itemcode + 템플릿 5종
- cupang_db 전용(JSON 폴백 없음). CUPANG_DB_URL 미설정 시 안내 페이지
- 월간 달력 + 출고 묶음(헤더+라인), 박스 입수량 자동계산(서버 재계산)
- 입고센터 관리(사용중 soft delete), 박스규칙 upsert, 엑셀 내보내기
- 상품 검색은 itemcode_db 읽기 전용(미설정 시 수동 입력)
- MODULE_KEYS/메뉴/아이콘/라벨 동기화, scripts/sql/cupang_db_init.sql(멱등)
- app/data/ gitignore 추가(PII)

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

app/modules/cupang/templates/cupang/box_rules.html

@@ -0,0 +1,66 @@
+{% extends "erp_base.html" %}
+
+{% block head_extra %}<link rel="stylesheet" href="/static/cupang.css" />{% endblock %}
+
+{% block content %}
+<section class="cpg">
+
+  <div class="erp-page-actions">
+    <a class="erp-btn erp-btn-outline" href="/cupang/">← 달력</a>
+  </div>
+
+  <!-- 추가/수정 (product_code UNIQUE → upsert) -->
+  <div class="erp-card cpg-form-card">
+    <div class="cpg-card-head">
+      <h2>박스 입수량 추가 / 수정</h2>
+      <span class="erp-muted">같은 제품코드는 덮어씁니다. 쿠팡박스 1박스당 들어가는 수량.</span>
+    </div>
+    <form method="post" action="/cupang/box-rules" class="cpg-rule-grid">
+      <label class="erp-field"><span>제품코드 *</span>
+        <input class="erp-input" type="text" name="product_code" required placeholder="예: MS-1001" /></label>
+      <label class="erp-field"><span>제품명(스냅샷)</span>
+        <input class="erp-input" type="text" name="product_name_snapshot" placeholder="예: 미라네 1호세트" /></label>
+      <label class="erp-field"><span>박스명</span>
+        <input class="erp-input" type="text" name="box_name" value="쿠팡박스" /></label>
+      <label class="erp-field"><span>박스당 입수량 *</span>
+        <input class="erp-input" type="number" name="units_per_box" min="1" required /></label>
+      <label class="erp-field cpg-full"><span>메모</span>
+        <input class="erp-input" type="text" name="memo" /></label>
+      <div><button type="submit" class="erp-btn erp-btn-primary">저장</button></div>
+    </form>
+  </div>
+
+  <!-- 목록 -->
+  <div class="erp-card cpg-form-card">
+    <div class="cpg-card-head"><h2>입수량 규칙 ({{ box_rules|length }})</h2></div>
+    <div class="erp-table-wrap">
+      <table class="erp-table">
+        <thead>
+          <tr><th>제품코드</th><th>제품명</th><th>박스명</th><th>입수량</th><th>상태</th><th>메모</th><th></th></tr>
+        </thead>
+        <tbody>
+          {% for r in box_rules %}
+          <tr {% if not r.active %}style="opacity:.55"{% endif %}>
+            <td>{{ r.product_code }}</td>
+            <td>{{ r.product_name_snapshot or '—' }}</td>
+            <td>{{ r.box_name }}</td>
+            <td>{{ r.units_per_box }}</td>
+            <td>{% if r.active %}<span class="erp-badge erp-badge-success">활성</span>{% else %}<span class="erp-badge erp-badge-neutral">비활성</span>{% endif %}</td>
+            <td>{{ r.memo or '—' }}</td>
+            <td>
+              {% if r.active %}
+              <form method="post" action="/cupang/box-rules/{{ r.id }}/delete" class="cpg-inline-form"
+                    onsubmit="return confirm('비활성화합니다. 계속할까요?');">
+                <button type="submit" class="erp-btn erp-btn-danger">비활성화</button>
+              </form>
+              {% else %}—{% endif %}
+            </td>
+          </tr>
+          {% endfor %}
+        </tbody>
+      </table>
+    </div>
+  </div>
+
+</section>
+{% endblock %}