fix(ui): 报告复制在 HTTP 非安全上下文下失效，增加 execCommand 降级

Claude-Session: https://claude.ai/code/session_01Bs2rrsVHUBTxRusm9espwB

web/src/app/(main)/function/tasks/detail/_tabs/report-tab.tsx

@@ -10,6 +10,34 @@ import { Button } from "@/components/ui/button";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { api } from "@/lib/api";
 
+async function copyText(text: string): Promise<boolean> {
+  // 优先使用异步剪贴板 API（仅在 HTTPS / localhost 等安全上下文可用）
+  if (navigator.clipboard && window.isSecureContext) {
+    try {
+      await navigator.clipboard.writeText(text);
+      return true;
+    } catch {
+      // 继续走降级方案
+    }
+  }
+  // 降级：HTTP 等非安全上下文下用 execCommand
+  try {
+    const textarea = document.createElement("textarea");
+    textarea.value = text;
+    textarea.style.position = "fixed";
+    textarea.style.left = "-9999px";
+    textarea.style.top = "0";
+    document.body.appendChild(textarea);
+    textarea.focus();
+    textarea.select();
+    const ok = document.execCommand("copy");
+    document.body.removeChild(textarea);
+    return ok;
+  } catch {
+    return false;
+  }
+}
+
 export function ReportTab({ taskId }: { taskId: string }) {
   const [report, setReport] = React.useState<string>("");
   const [loading, setLoading] = React.useState(true);
@@ -34,12 +62,16 @@ export function ReportTab({ taskId }: { taskId: string }) {
     };
   }, [taskId]);
 
-  function copy() {
+  async function copy() {
     if (!report) return;
-    navigator.clipboard?.writeText(report);
-    setCopied(true);
-    toast.success("已复制 Markdown");
-    setTimeout(() => setCopied(false), 1500);
+    const ok = await copyText(report);
+    if (ok) {
+      setCopied(true);
+      toast.success("已复制 Markdown");
+      setTimeout(() => setCopied(false), 1500);
+    } else {
+      toast.error("复制失败，请手动选择文本复制");
+    }
   }
 
   let content: React.ReactNode;