feat(cupang): 제품명 카탈로그 설정 + 달력 공휴일 색상 + 폼 UI 개선

- 설정 화면 추가: /cupang/products — itemcode_db 검색 등록 + 수동 등록.
  제품명 드롭다운 소스. cupang_products 테이블 신규(init.sql 멱등 재실행 필요)
- 폼 품목라인: 제품명 드롭다운 선택 → 제품코드 자동 입력
- 라인 컬럼 순서 제품명·제품코드·수량·입수량·박스계산·메모
- 제품코드 140px, 수량·입수량 60px 폭 고정
- 공통 헤더 입력란 겹침 수정(min-width:0, width:100%, box-sizing)
- 달력: 일/공휴일 빨강, 토 파랑, 글자 크기 확대. 한국 공휴일 모듈(holidays.py)
- document_no null → "None" 출력 버그 수정

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

app/modules/cupang/router.py

@@ -23,6 +23,7 @@ from fastapi.responses import (
     StreamingResponse,
 )
 
+from .holidays import is_holiday
 from .store import DEFAULT_CENTERS, SHEET_COLUMNS, SHIP_METHODS, STATUSES, compute_boxes
 
 router = APIRouter(prefix="/cupang", tags=["cupang"])
@@ -153,6 +154,9 @@ async def index(request: Request) -> HTMLResponse:
                 "in_month": d.month == month,
                 "is_today": d == today,
                 "is_selected": d.isoformat() == sel,
+                "is_sunday": d.weekday() == 6,
+                "is_saturday": d.weekday() == 5,
+                "is_holiday": is_holiday(d),
                 "counts": counts.get(d.isoformat(), {}),
             }
             for d in week
@@ -212,6 +216,7 @@ def _form_context(request: Request, store: Any, user: dict[str, Any]) -> dict[st
         "nav_items": build_erp_nav(user, active="cupang"),
         "centers": store.list_centers(),
         "box_rules": store.list_box_rules(),
+        "products": store.list_products(),
         "ship_methods": list(SHIP_METHODS),
         "statuses": list(STATUSES),
         "search_enabled": bool(reader and reader.enabled),
@@ -583,6 +588,71 @@ async def box_rule_delete(
     return RedirectResponse(url="/cupang/box-rules", status_code=303)
 
 
+# ════════════════════════════════════════════════════════════
+# 설정 — 제품명 카탈로그 관리 (itemcode_db 에서 등록)
+# ════════════════════════════════════════════════════════════
+@router.get("/products", response_class=HTMLResponse)
+async def products_page(request: Request) -> HTMLResponse:
+    from app.main import build_erp_nav, render_template  # noqa: WPS433
+    from app.store import is_admin  # noqa: WPS433
+
+    guard = _guard(request)
+    if not isinstance(guard, tuple):
+        return guard
+    store, user = guard
+    reader = _itemcode(request)
+    return render_template(
+        request,
+        "cupang/products.html",
+        {
+            "user": user,
+            "is_admin": is_admin(user),
+            "nav_items": build_erp_nav(user, active="cupang"),
+            "page_title": "쿠팡 밀크런 — 설정 (제품명)",
+            "page_subtitle": "제품명 리스트 관리. itemcode_db 에서 검색해 등록하면 폼 드롭다운에 노출됩니다.",
+            "products": store.list_products(include_inactive=True),
+            "search_enabled": bool(reader and reader.enabled),
+            "search_reason": (reader.reason if reader else ""),
+        },
+    )
+
+
+@router.post("/products")
+async def product_upsert(
+    request: Request,
+    product_code: str = Form(...),
+    product_name: str = Form(...),
+    sort_order: int = Form(0),
+    user: dict[str, Any] = Depends(_require_user),
+) -> RedirectResponse:
+    store = _store(request)
+    if store is None:
+        raise HTTPException(status_code=503, detail="cupang_db 미설정")
+    try:
+        store.upsert_product(
+            product_code=product_code, product_name=product_name, sort_order=sort_order
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+    return RedirectResponse(url="/cupang/products", status_code=303)
+
+
+@router.post("/products/{product_id:int}/delete")
+async def product_delete(
+    request: Request,
+    product_id: int,
+    user: dict[str, Any] = Depends(_require_user),
+) -> RedirectResponse:
+    store = _store(request)
+    if store is None:
+        raise HTTPException(status_code=503, detail="cupang_db 미설정")
+    try:
+        store.deactivate_product(product_id=product_id)
+    except KeyError:
+        raise HTTPException(status_code=404, detail="제품을 찾을 수 없습니다.")
+    return RedirectResponse(url="/cupang/products", status_code=303)
+
+
 # ════════════════════════════════════════════════════════════
 # 상품 검색 (itemcode_db 읽기 전용) + 박스 계산 미리보기
 # ════════════════════════════════════════════════════════════