feat: 에러 처리 개선 + 커스텀 확인 모달 + 관리자 테스트

- 에러 코드 기반 한국어 매핑 (8개 코드, parseError 개선)
- window.confirm → 커스텀 ConfirmDialog (다크 테마, Promise 기반)
- launch URL 파라미터 ticket → token 통일
- 관리자 테스트 27개 추가 (공지사항 12 + 다운로드 6 + 유저 9)

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

src/components/confirm/Confirm.css

@@ -0,0 +1,76 @@
+.confirm-overlay {
+  position: fixed;
+  inset: 0;
+  z-index: 10001;
+  background: rgba(0, 0, 0, 0.6);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  animation: confirm-fade-in 0.15s ease-out;
+}
+
+.confirm-dialog {
+  background: #3a3a3a;
+  border: 1px solid rgba(186, 205, 176, 0.15);
+  border-radius: 12px;
+  padding: 24px;
+  min-width: 320px;
+  max-width: 420px;
+  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
+  animation: confirm-scale-in 0.15s ease-out;
+}
+
+.confirm-message {
+  font-size: 0.95rem;
+  color: rgba(255, 255, 255, 0.87);
+  line-height: 1.5;
+  margin: 0 0 20px 0;
+}
+
+.confirm-actions {
+  display: flex;
+  justify-content: flex-end;
+  gap: 8px;
+}
+
+.confirm-btn {
+  padding: 8px 20px;
+  border-radius: 6px;
+  font-size: 0.9rem;
+  font-weight: 500;
+  cursor: pointer;
+  border: none;
+  transition: opacity 0.2s;
+}
+
+.confirm-btn:hover {
+  opacity: 0.85;
+}
+
+.confirm-btn-cancel {
+  background: transparent;
+  color: rgba(255, 255, 255, 0.5);
+  border: 1px solid rgba(255, 255, 255, 0.15);
+}
+
+.confirm-btn-ok {
+  background: #BACDB0;
+  color: #2E2C2F;
+  font-weight: 600;
+}
+
+@keyframes confirm-fade-in {
+  from { opacity: 0; }
+  to { opacity: 1; }
+}
+
+@keyframes confirm-scale-in {
+  from {
+    opacity: 0;
+    transform: scale(0.95);
+  }
+  to {
+    opacity: 1;
+    transform: scale(1);
+  }
+}