fix(admin): 修复设置页面 CSP style-src 违规导致加载失败

- 移除 site-settings 模板中的内联 style 属性（display:none, width:100px）
- 将内联样式迁移至 site-settings.css 的 CSS 类中
- site-settings-theme.js 用 className 替代 style.display 操作

templates/admin/static/css/site-settings.css

@@ -141,6 +141,13 @@
     font-size: 13px; color: var(--text-muted);
 }
 
+/* --- 隐藏工具类 --- */
+#theme-status { display: none; }
+#theme-status.visible { display: block; }
+
+/* --- 窄输入框 --- */
+.setting-input-narrow { width: 100px; }
+
 /* --- 主题状态提示 --- */
 .status-success .section-body {
     background: #e8f5e9; border-left: 3px solid #4caf50;

templates/admin/static/js/site-settings-theme.js

@@ -95,8 +95,7 @@
     }
 
     function showStatus(msg, type) {
-        statusSection.style.display = 'block';
-        statusSection.className = 'settings-section';
+        statusSection.className = 'settings-section visible';
         if (type === 'success') {
             statusSection.classList.add('status-success');
         } else if (type === 'error') {