refactor: 清理未使用的源码片段

src/components/TaskForm.vue

@@ -276,7 +276,6 @@ const isMobile = computed(() => screenWidth.value <= 900);
 // 学习材料 Markdown 预览
 const showPreview = ref(false);
 const materialPreview = ref("");
-const previewLoading = ref(false);
 
 const escapeHtml = (s: string) => s.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
 const escapeAttr = (s: string) => s.replace(/"/g, "&quot;").replace(/&/g, "&amp;");
@@ -312,20 +311,15 @@ async function previewMaterial() {
   showPreview.value = true;
   const raw = materialUrl.value || "";
   if (!raw.trim()) { materialPreview.value = ""; return; }
-  previewLoading.value = true;
-  try {
-    const titles: Record<string, string> = {};
-    const bareUrls = new Set<string>();
-    raw.replace(/https?:\/\/[^\s)\u3001\uFF09\u300D\u300B<>]+/g, (url) => {
-      bareUrls.add(url.replace(/[.。,，;；!！?？）】」』\]]+$/, ""));
-      return url;
-    });
-    const results = await Promise.all([...bareUrls].map(async (u) => ({ u, t: await getUrlTitle(u) })));
-    results.forEach(({ u, t }) => { titles[u] = t; });
-    materialPreview.value = renderMarkdown(raw, titles);
-  } finally {
-    previewLoading.value = false;
-  }
+  const titles: Record<string, string> = {};
+  const bareUrls = new Set<string>();
+  raw.replace(/https?:\/\/[^\s)\u3001\uFF09\u300D\u300B<>]+/g, (url) => {
+    bareUrls.add(url.replace(/[.。,，;；!！?？）】」』\]]+$/, ""));
+    return url;
+  });
+  const results = await Promise.all([...bareUrls].map(async (u) => ({ u, t: await getUrlTitle(u) })));
+  results.forEach(({ u, t }) => { titles[u] = t; });
+  materialPreview.value = renderMarkdown(raw, titles);
 }
 </script>