fix(frontend): bundle tdesign-icons sprite locally for offline deploys

The <t-icon> component from tdesign-vue-next lazily loads its SVG sprite
from https://tdesign.gtimg.com/icon/<ver>/fonts/index.js at runtime. In
air-gapped or intranet deployments this request fails and the whole UI
loses its icons (agent cards, knowledge-base breadcrumbs/cards, upload
buttons, etc.).

Ship the sprite (tdesign-icons-vue-next@0.4.1) as a static asset under
frontend/public/tdesign-icons/0.4.1/fonts/index.js and preload it from
index.html so every <t-icon name="..."> resolves against local symbols.
An offline guard injects stub <script>/<link> nodes that match tdesign's
dedup selectors, so checkScriptAndLoad / checkLinkAndLoad short-circuit
without ever hitting the CDN (covers both the 0.4.0 and 0.4.1 hardcoded
URLs for forward-compat).

Closes #867
Closes #897

frontend/index.html

@@ -57,6 +57,12 @@
 })();
 </script>
 <script src="/config.js"></script>
+<!--
+  离线部署兼容：提前本地加载 tdesign-icons SVG sprite，避免 tdesign-vue-next 的
+  <t-icon> 运行时向 https://tdesign.gtimg.com 发起请求（见 issue #867 / #897）。
+  升级 tdesign-icons-vue-next 时需同步更新 public/tdesign-icons/<version>/fonts/index.js。
+-->
+<script src="/tdesign-icons/0.4.1/fonts/index.js"></script>
 <div id="app"></div>
 <script>
 (function(){

frontend/src/main.ts

@@ -10,6 +10,10 @@ import "@/assets/theme/theme.css";
 import "@/assets/dropdown-menu.less";
 import i18n from "./i18n";
 import { initTheme } from "@/composables/useTheme";
+import { installTDesignIconOfflineGuard } from "@/utils/tdesign-icon-offline";
+
+// 必须在 Vue 组件挂载之前执行，避免 tdesign-icons 运行时请求 tdesign.gtimg.com
+installTDesignIconOfflineGuard();
 
 initTheme();
 

frontend/src/utils/tdesign-icon-offline.ts

@@ -0,0 +1,81 @@
+/**
+ * 阻断 tdesign-icons-vue-next 对外网 CDN 的 iconfont 请求。
+ *
+ * 背景（issue #867 / #897）：
+ *   tdesign-icons-vue-next 的 Icon / IconFont 组件在 onMounted 时会通过
+ *   `checkScriptAndLoad` / `checkLinkAndLoad` 往 document 里注入指向
+ *   `https://tdesign.gtimg.com/icon/<version>/fonts/index.(js|css)` 的
+ *   <script> / <link>。在无外网环境下请求会失败，导致图标全部不渲染。
+ *
+ * 处理方式：在 Vue app 挂载之前预先插入符合 tdesign 匹配规则的占位节点，
+ *   让 `checkScriptAndLoad` / `checkLinkAndLoad` 的去重判断命中、直接返回，
+ *   不再追加指向 CDN 的真实节点。
+ *
+ *   - 匹配选择器来源：tdesign-icons-vue-next/esm/utils/check-url-and-load.js
+ *       `.t-svg-js-stylesheet--unique-class[src="<url>"]`
+ *       `.t-iconfont-stylesheet--unique-class[href="<url>"]`
+ *   - 占位 <script> / <link> 使用非标准 type / rel，浏览器不会真正发起网络请求。
+ *
+ * SVG sprite 的符号则通过 index.html 中的 <script src="/tdesign-icons/.../index.js"></script>
+ * 在本地提前注册，因此 <t-icon name="..."> 仍可正常渲染。
+ */
+
+const SVG_SCRIPT_CLASS = "t-svg-js-stylesheet--unique-class";
+const ICONFONT_LINK_CLASS = "t-iconfont-stylesheet--unique-class";
+
+// 对齐 tdesign-icons-vue-next 0.4.x 内部硬编码的地址；多版本号并存以兼容潜在升级。
+const BLOCKED_SCRIPT_URLS = [
+  "https://tdesign.gtimg.com/icon/0.4.0/fonts/index.js",
+  "https://tdesign.gtimg.com/icon/0.4.1/fonts/index.js",
+];
+
+const BLOCKED_LINK_URLS = [
+  "https://tdesign.gtimg.com/icon/0.4.0/fonts/index.css",
+  "https://tdesign.gtimg.com/icon/0.4.1/fonts/index.css",
+];
+
+let installed = false;
+
+export function installTDesignIconOfflineGuard(): void {
+  if (installed || typeof document === "undefined") return;
+  installed = true;
+
+  const body = document.body;
+  if (!body) {
+    document.addEventListener(
+      "DOMContentLoaded",
+      () => installTDesignIconOfflineGuard(),
+      { once: true },
+    );
+    installed = false;
+    return;
+  }
+
+  BLOCKED_SCRIPT_URLS.forEach((src) => {
+    const exists = document.querySelector(
+      `script.${SVG_SCRIPT_CLASS}[src="${src}"]`,
+    );
+    if (exists) return;
+    const stub = document.createElement("script");
+    stub.setAttribute("class", SVG_SCRIPT_CLASS);
+    stub.setAttribute("src", src);
+    // 非标准 MIME 类型会让浏览器跳过脚本的 fetch/执行阶段
+    stub.setAttribute("type", "text/no-load");
+    stub.setAttribute("data-weknora-blocked-cdn", "tdesign-icons");
+    body.appendChild(stub);
+  });
+
+  BLOCKED_LINK_URLS.forEach((href) => {
+    const exists = document.querySelector(
+      `link.${ICONFONT_LINK_CLASS}[href="${href}"]`,
+    );
+    if (exists) return;
+    const stub = document.createElement("link");
+    stub.setAttribute("class", ICONFONT_LINK_CLASS);
+    stub.setAttribute("href", href);
+    // 不声明 rel="stylesheet"，浏览器不会发起样式表请求
+    stub.setAttribute("rel", "preload-blocked");
+    stub.setAttribute("data-weknora-blocked-cdn", "tdesign-icons");
+    document.head.appendChild(stub);
+  });
+}