feat: 소수 환자 약품 뱃지 표시

- 1년간 3명 이하 환자만 사용하는 약품에 환자 이름 뱃지 표시
- 조회 기간 내 사용한 환자는 핑크색으로 강조
- 매출액 컬럼명 변경 (약가 → 매출액)
- SUM(DRUPRICE)로 매출액 계산

backend/templates/admin_rx_usage.html

@@ -391,6 +391,28 @@
             font-family: inherit;
         }
 
+        .patient-badge {
+            display: inline-block;
+            background: rgba(156, 163, 175, 0.15);
+            color: #9ca3af;
+            font-size: 10px;
+            font-weight: 500;
+            padding: 2px 6px;
+            border-radius: 4px;
+            margin-left: 4px;
+            font-family: inherit;
+        }
+
+        .patient-badge.has-today {
+            background: rgba(236, 72, 153, 0.2);
+            color: #ec4899;
+        }
+
+        .today-patient {
+            color: #ec4899;
+            font-weight: 700;
+        }
+
         /* 수량 관련 */
         .qty-cell {
             text-align: center;
@@ -957,7 +979,7 @@
                             }
                             <div class="product-info">
                                 <span class="product-name">${escapeHtml(item.product_name)}</span>
-                                <span class="product-code">${item.drug_code}${item.supplier ? ` · ${escapeHtml(item.supplier)}` : ''}${item.location ? ` <span class="location-badge">📍${escapeHtml(item.location)}</span>` : ''}</span>
+                                <span class="product-code">${item.drug_code}${item.supplier ? ` · ${escapeHtml(item.supplier)}` : ''}${item.location ? ` <span class="location-badge">📍${escapeHtml(item.location)}</span>` : ''}${item.patient_names ? ` <span class="patient-badge ${item.today_patients ? 'has-today' : ''}" title="${item.patient_count}명 사용${item.today_patients ? ' (오늘: ' + item.today_patients + ')' : ''}">👤${formatPatientNames(item.patient_names, item.today_patients)}</span>` : ''}</span>
                             </div>
                         </div>
                     </td>
@@ -1861,6 +1883,23 @@
         return str.replace(/[&<>"']/g, m => ({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;',"'":'&#39;'}[m]));
     }
 
+    // 환자 이름 포맷 (오늘 사용 환자 강조)
+    function formatPatientNames(allNames, todayNames) {
+        if (!allNames) return '';
+        if (!todayNames) return escapeHtml(allNames);
+        
+        const todaySet = new Set(todayNames.split(', ').map(n => n.trim()));
+        const names = allNames.split(', ');
+        
+        return names.map(name => {
+            const trimmed = name.trim();
+            if (todaySet.has(trimmed)) {
+                return `<strong class="today-patient">${escapeHtml(trimmed)}</strong>`;
+            }
+            return escapeHtml(trimmed);
+        }).join(', ');
+    }
+
     function showToast(message, type = 'info') {
         const toast = document.getElementById('toast');
         toast.textContent = message;