feat(반품관리): 약품 더블클릭 시 입고이력 모달 추가

- admin_return_management.html 업데이트:
  - 입고이력 모달 스타일/HTML 추가 (다크테마 적용)
  - tr ondblclick → openPurchaseModal()
  - 도매상 전화번호 클릭 시 복사 기능
  - 테이블 위에 더블클릭 힌트 추가
  - 상태변경 버튼에 event.stopPropagation() 추가

backend/templates/admin_return_management.html

@@ -544,6 +544,138 @@
             .filter-group select, .filter-group input { width: 100%; }
             .urgency-tabs { flex-wrap: wrap; }
         }
+
+        /* ══════════════════ 입고이력 모달 ══════════════════ */
+        .purchase-modal {
+            position: fixed;
+            inset: 0;
+            background: rgba(0,0,0,0.8);
+            display: none;
+            align-items: center;
+            justify-content: center;
+            z-index: 1100;
+            backdrop-filter: blur(4px);
+        }
+        .purchase-modal.open { display: flex; }
+        .purchase-modal-content {
+            background: var(--bg-card);
+            border-radius: 20px;
+            width: 95%;
+            max-width: 650px;
+            max-height: 80vh;
+            overflow: hidden;
+            display: flex;
+            flex-direction: column;
+            border: 1px solid var(--border);
+            box-shadow: 0 20px 60px rgba(0,0,0,0.5);
+        }
+        .purchase-modal-header {
+            padding: 20px 24px;
+            background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
+            color: #fff;
+        }
+        .purchase-modal-header h3 {
+            margin: 0 0 6px 0;
+            font-size: 18px;
+            display: flex;
+            align-items: center;
+            gap: 8px;
+        }
+        .purchase-modal-header .drug-name {
+            font-size: 14px;
+            opacity: 0.9;
+        }
+        .purchase-modal-body {
+            padding: 16px 24px 24px;
+            overflow-y: auto;
+            flex: 1;
+        }
+        .purchase-history-table {
+            width: 100%;
+            border-collapse: collapse;
+        }
+        .purchase-history-table th {
+            background: var(--bg-secondary);
+            padding: 12px 10px;
+            font-size: 12px;
+            font-weight: 600;
+            color: var(--text-secondary);
+            text-align: left;
+            border-bottom: 2px solid var(--border);
+            position: sticky;
+            top: 0;
+        }
+        .purchase-history-table td {
+            padding: 14px 10px;
+            font-size: 13px;
+            border-bottom: 1px solid var(--border);
+            color: var(--text-primary);
+        }
+        .purchase-history-table tr:hover td {
+            background: var(--bg-card-hover);
+        }
+        .supplier-name {
+            font-weight: 600;
+            color: var(--accent-cyan);
+        }
+        .supplier-tel {
+            font-size: 12px;
+            color: var(--accent-blue);
+            cursor: pointer;
+        }
+        .supplier-tel:hover {
+            text-decoration: underline;
+        }
+        .purchase-date {
+            color: var(--text-secondary);
+            font-family: 'JetBrains Mono', monospace;
+            font-size: 12px;
+        }
+        .purchase-qty {
+            font-weight: 600;
+            color: var(--accent-emerald);
+        }
+        .purchase-price {
+            color: var(--accent-gold);
+            font-family: 'JetBrains Mono', monospace;
+        }
+        .purchase-empty {
+            text-align: center;
+            padding: 40px 20px;
+            color: var(--text-muted);
+        }
+        .purchase-empty .icon {
+            font-size: 40px;
+            margin-bottom: 12px;
+        }
+        .purchase-modal-footer {
+            padding: 16px 24px;
+            border-top: 1px solid var(--border);
+            display: flex;
+            justify-content: flex-end;
+        }
+        .purchase-modal-btn {
+            padding: 10px 24px;
+            border: none;
+            border-radius: 8px;
+            cursor: pointer;
+            font-weight: 500;
+            font-size: 14px;
+            background: var(--bg-secondary);
+            color: var(--text-secondary);
+            transition: all 0.15s;
+        }
+        .purchase-modal-btn:hover {
+            background: var(--bg-card-hover);
+            color: var(--text-primary);
+        }
+        /* 테이블 행 더블클릭 가능 표시 */
+        #dataTableBody tr {
+            cursor: pointer;
+        }
+        #dataTableBody tr:active {
+            background: var(--bg-card-hover) !important;
+        }
     </style>
 </head>
 <body>
@@ -673,6 +805,9 @@
         </div>
 
         <!-- 데이터 테이블 -->
+        <div style="margin-bottom: 8px; font-size: 12px; color: var(--text-muted);">
+            💡 행 더블클릭 → 입고이력 확인 (도매상 연락처)
+        </div>
         <div class="table-wrap">
             <table class="data-table">
                 <thead>
@@ -742,6 +877,34 @@
     <!-- 토스트 -->
     <div class="toast" id="toast"></div>
 
+    <!-- 입고이력 모달 -->
+    <div class="purchase-modal" id="purchaseModal">
+        <div class="purchase-modal-content">
+            <div class="purchase-modal-header">
+                <h3>📦 입고 이력</h3>
+                <div class="drug-name" id="purchaseDrugName">-</div>
+            </div>
+            <div class="purchase-modal-body">
+                <table class="purchase-history-table">
+                    <thead>
+                        <tr>
+                            <th>도매상</th>
+                            <th>입고일</th>
+                            <th>수량</th>
+                            <th>단가</th>
+                        </tr>
+                    </thead>
+                    <tbody id="purchaseHistoryBody">
+                        <tr><td colspan="4" class="purchase-empty"><div class="icon">📭</div><p>로딩 중...</p></td></tr>
+                    </tbody>
+                </table>
+            </div>
+            <div class="purchase-modal-footer">
+                <button class="purchase-modal-btn" onclick="closePurchaseModal()">닫기</button>
+            </div>
+        </div>
+    </div>
+
     <script>
     let allData = [];
     let currentPage = 1;
@@ -869,7 +1032,7 @@
             const hasAmount = item.recoverable_amount && item.recoverable_amount > 0;
             
             return `
-                <tr class="${urgencyClass}">
+                <tr class="${urgencyClass}" ondblclick="openPurchaseModal('${item.drug_code}', '${escapeHtml(item.drug_name).replace(/'/g, "\\'")}')">
                     <td>
                         <span class="urgency-badge ${urgency}">
                             ${urgency === 'critical' ? '🔴' : urgency === 'warning' ? '🟠' : '⚪'}
@@ -891,7 +1054,7 @@
                     <td class="date-cell">${formatDate(item.last_purchase_date) || '-'}</td>
                     <td><span class="status-badge ${item.status}">${getStatusLabel(item.status)}</span></td>
                     <td>
-                        <button class="action-btn primary" onclick="openStatusModal(${item.id})">상태 변경</button>
+                        <button class="action-btn primary" onclick="event.stopPropagation();openStatusModal(${item.id})">상태 변경</button>
                     </td>
                 </tr>
             `;
@@ -1044,6 +1207,67 @@
         toast.className = 'toast show ' + type;
         setTimeout(() => { toast.classList.remove('show'); }, 3000);
     }
+
+    // ══════════════════ 입고이력 모달 ══════════════════
+    async function openPurchaseModal(drugCode, drugName) {
+        const modal = document.getElementById('purchaseModal');
+        const nameEl = document.getElementById('purchaseDrugName');
+        const tbody = document.getElementById('purchaseHistoryBody');
+        
+        nameEl.textContent = drugName || drugCode;
+        tbody.innerHTML = '<tr><td colspan="4" class="purchase-empty"><div class="icon">⏳</div><p>입고이력 조회 중...</p></td></tr>';
+        modal.classList.add('open');
+        
+        try {
+            const res = await fetch(`/api/drugs/${drugCode}/purchase-history`);
+            const data = await res.json();
+            
+            if (data.success) {
+                if (data.history.length === 0) {
+                    tbody.innerHTML = '<tr><td colspan="4" class="purchase-empty"><div class="icon">📭</div><p>입고 이력이 없습니다</p></td></tr>';
+                } else {
+                    tbody.innerHTML = data.history.map(h => `
+                        <tr>
+                            <td>
+                                <div class="supplier-name">${escapeHtml(h.supplier)}</div>
+                                ${h.supplier_tel ? `<div class="supplier-tel" onclick="event.stopPropagation();copyToClipboard('${h.supplier_tel}')" title="클릭하여 복사">📞 ${h.supplier_tel}</div>` : ''}
+                            </td>
+                            <td class="purchase-date">${h.date}</td>
+                            <td class="purchase-qty">${h.quantity.toLocaleString()}</td>
+                            <td class="purchase-price">${h.unit_price ? formatPrice(h.unit_price) : '-'}</td>
+                        </tr>
+                    `).join('');
+                }
+            } else {
+                tbody.innerHTML = `<tr><td colspan="4" class="purchase-empty"><div class="icon">⚠️</div><p>조회 실패: ${data.error}</p></td></tr>`;
+            }
+        } catch (err) {
+            tbody.innerHTML = `<tr><td colspan="4" class="purchase-empty"><div class="icon">❌</div><p>오류: ${err.message}</p></td></tr>`;
+        }
+    }
+    
+    function closePurchaseModal() {
+        document.getElementById('purchaseModal').classList.remove('open');
+    }
+    
+    function copyToClipboard(text) {
+        navigator.clipboard.writeText(text).then(() => {
+            showToast(`📋 ${text} 복사됨`, 'success');
+        }).catch(() => {
+            const input = document.createElement('input');
+            input.value = text;
+            document.body.appendChild(input);
+            input.select();
+            document.execCommand('copy');
+            document.body.removeChild(input);
+            showToast(`📋 ${text} 복사됨`, 'success');
+        });
+    }
+    
+    // 모달 외부 클릭 시 닫기
+    document.getElementById('purchaseModal').addEventListener('click', function(e) {
+        if (e.target === this) closePurchaseModal();
+    });
     </script>
 </body>
 </html>