feat: 完善外部资源备用机制和日志系统

- 在header.php中添加用户角色检测，传递给前端JavaScript
- 更新Open Sans字体CSS文件，支持本地woff2字体文件备用
- 修改footer.php中MathJax 3/2和KaTeX加载机制，添加onerror备用处理
- 优化resource-loader.js日志系统，使用ArgonLogger替代console.log
- 仅管理员用户显示控制台日志，普通用户和游客不显示调试信息
- 完善资源加载错误处理，统一使用ArgonLogger记录警告信息

assets/vendor/external/fonts/font-fallback.css

@@ -0,0 +1,72 @@
+/* 字体备用系统 - 确保在任何情况下都有合适的字体显示 */
+
+/* 全局字体备用栈 */
+:root {
+    --font-family-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
+    --font-family-serif: Georgia, Cambria, "Times New Roman", Times, serif;
+    --font-family-mono: Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
+    --font-family-chinese: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
+}
+
+/* 当 Open Sans 不可用时的备用 */
+body, .open-sans-fallback {
+    font-family: "Open Sans", var(--font-family-sans);
+}
+
+/* 当 Noto Serif SC 不可用时的备用 */
+.noto-serif-fallback {
+    font-family: "Noto Serif SC", var(--font-family-chinese), var(--font-family-serif);
+}
+
+/* 通用中文字体备用 */
+.chinese-text {
+    font-family: var(--font-family-chinese);
+}
+
+/* 确保代码字体始终可用 */
+code, pre, .monospace {
+    font-family: var(--font-family-mono);
+}
+
+/* 字体加载失败时的样式调整 */
+.font-loading-error {
+    font-family: var(--font-family-sans) !important;
+}
+
+.font-loading-error::before {
+    content: "";
+    display: inline-block;
+    width: 0;
+    height: 0;
+}
+
+/* 响应式字体大小 */
+@media (max-width: 768px) {
+    body {
+        font-size: 14px;
+        line-height: 1.5;
+    }
+}
+
+@media (min-width: 769px) {
+    body {
+        font-size: 16px;
+        line-height: 1.6;
+    }
+}
+
+/* 确保图标字体备用 */
+.fa, .fas, .far, .fal, .fab {
+    font-family: "Font Awesome 5 Free", "Font Awesome 5 Pro", "FontAwesome", sans-serif;
+}
+
+/* 当图标字体不可用时显示文字 */
+.fa-home::after { content: "首页"; }
+.fa-user::after { content: "用户"; }
+.fa-search::after { content: "搜索"; }
+.fa-menu::after { content: "菜单"; }
+.fa-close::after { content: "关闭"; }
+.fa-arrow-left::after { content: "←"; }
+.fa-arrow-right::after { content: "→"; }
+.fa-arrow-up::after { content: "↑"; }
+.fa-arrow-down::after { content: "↓"; }

assets/vendor/external/fonts/open-sans.css

@@ -1,32 +1,50 @@
-/* Open Sans Font - Local Fallback */
+/* Open Sans Font - 完整本地备用版本 */
+
+/* 300 weight - latin */
 @font-face {
   font-family: 'Open Sans';
   font-style: normal;
   font-weight: 300;
   font-display: swap;
-  src: local('Open Sans Light'), local('OpenSans-Light');
+  src: url('files/opensans-300-latin.woff2') format('woff2'),
+       local('Open Sans Light'), local('OpenSans-Light');
+  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }
 
+/* 400 weight - latin */
 @font-face {
   font-family: 'Open Sans';
   font-style: normal;
   font-weight: 400;
   font-display: swap;
-  src: local('Open Sans Regular'), local('OpenSans-Regular');
+  src: url('files/opensans-400-latin.woff2') format('woff2'),
+       local('Open Sans Regular'), local('OpenSans-Regular');
+  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }
 
+/* 600 weight - latin */
 @font-face {
   font-family: 'Open Sans';
   font-style: normal;
   font-weight: 600;
   font-display: swap;
-  src: local('Open Sans SemiBold'), local('OpenSans-SemiBold');
+  src: url('files/opensans-600-latin.woff2') format('woff2'),
+       local('Open Sans SemiBold'), local('OpenSans-SemiBold');
+  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }
 
+/* 700 weight - latin */
 @font-face {
   font-family: 'Open Sans';
   font-style: normal;
   font-weight: 700;
   font-display: swap;
-  src: local('Open Sans Bold'), local('OpenSans-Bold');
+  src: url('files/opensans-700-latin.woff2') format('woff2'),
+       local('Open Sans Bold'), local('OpenSans-Bold');
+  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
+}
+
+/* 备用字体栈 */
+body, .font-sans-serif {
+  font-family: 'Open Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';
 }