v4.0.0: 덱 UX·i18n·썸네일 저장 개선 및 413 수정

즐겨찾기·홀드 미리보기·페이지 도움말·3개국어 번역을 추가하고, 덱 저장 시 썸네일을 1200px로 통일하며 Nginx/API 업로드 제한을 상향했다.

Co-authored-by: Cursor <cursoragent@cursor.com>

style/auth-header.css

@@ -2,68 +2,69 @@
     position: relative;
 }
 
-.auth-avatar-btn {
+.auth-profile-trigger {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.5rem;
+    max-width: 12.5rem;
+    padding: 0.125rem 0.5rem 0.125rem 0.125rem;
+    border: none;
+    border-radius: 9999px;
+    background: transparent;
+    cursor: pointer;
+    transition: background 0.2s, box-shadow 0.2s;
+}
+
+.auth-profile-trigger:hover {
+    background: #f1f5f9;
+}
+
+.auth-profile-trigger:focus-visible {
+    outline: none;
+    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
+}
+
+.auth-profile-trigger--guest {
+    padding: 0;
+}
+
+.auth-profile-trigger--named {
+    padding-right: 0.625rem;
+}
+
+.auth-avatar-circle {
+    flex-shrink: 0;
+    width: 36px;
     height: 36px;
     border-radius: 9999px;
     border: 2px solid #e2e8f0;
     background: #f1f5f9;
-    cursor: pointer;
-    overflow: hidden;
-    display: inline-flex;
-    align-items: center;
-    justify-content: center;
-    gap: 0;
-    padding: 0;
-    transition: border-color 0.2s, box-shadow 0.2s;
-}
-
-.auth-avatar-btn.auth-profile-btn--named {
-    padding-right: 12px;
-    gap: 8px;
-    max-width: 180px;
-}
-
-.auth-avatar-btn:hover {
-    border-color: #3b82f6;
-    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
-}
-
-.auth-avatar-wrap {
-    flex-shrink: 0;
-    width: 32px;
-    height: 32px;
-    margin: 2px;
-    border-radius: 9999px;
     overflow: hidden;
     display: flex;
     align-items: center;
     justify-content: center;
+    transition: border-color 0.2s;
 }
 
-.auth-avatar-wrap img {
+.auth-profile-trigger:hover .auth-avatar-circle {
+    border-color: #3b82f6;
+}
+
+.auth-avatar-circle img {
     width: 100%;
     height: 100%;
     object-fit: cover;
 }
 
 .auth-username {
-    font-size: 13px;
+    font-size: 0.8125rem;
     font-weight: 700;
     color: #334155;
     white-space: nowrap;
     overflow: hidden;
     text-overflow: ellipsis;
     min-width: 0;
-}
-
-.auth-avatar-btn:not(.auth-profile-btn--named) {
-    width: 36px;
-}
-
-.auth-avatar-btn:not(.auth-profile-btn--named) .auth-avatar-wrap {
-    width: 100%;
-    height: 100%;
-    margin: 0;
+    line-height: 1.2;
 }
 
 .auth-dropdown {