fix: 优化博主标识显示逻辑，支持图标模式

- 移除 adminBadge 为空的检查，允许仅通过邮箱识别博主
- 当未设置博主标签文字时，默认显示认证图标替代文本标签
- 更新管理后台标签说明，提示留空使用默认图标
- 添加博主图标专用样式，确保透明背景和正确颜色

cwd-admin/src/views/SettingsView.vue

@@ -22,7 +22,7 @@
           <input v-model="commentAdminEmail" class="form-input" type="email" />
         </div>
         <div class="form-item">
-          <label class="form-label">博主标签文字</label>
+          <label class="form-label">博主标签文字（留空使用默认图标）</label>
           <input v-model="commentAdminBadge" class="form-input" type="text" />
         </div>
         <div class="form-item">
@@ -468,7 +468,7 @@ async function load() {
     ]);
     email.value = notifyRes.email || "";
     commentAdminEmail.value = commentRes.adminEmail || "";
-    commentAdminBadge.value = commentRes.adminBadge || "博主";
+    commentAdminBadge.value = commentRes.adminBadge ?? "";
     avatarPrefix.value = commentRes.avatarPrefix || "";
     commentAdminEnabled.value = !!commentRes.adminEnabled;
     allowedDomains.value = commentRes.allowedDomains