fix: clear issue copy timer between clicks

ui/src/pages/IssueDetail.tsx

@@ -210,6 +210,7 @@ export function IssueDetail() {
   });
   const [attachmentError, setAttachmentError] = useState<string | null>(null);
   const [attachmentDragActive, setAttachmentDragActive] = useState(false);
+  const copiedTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const fileInputRef = useRef<HTMLInputElement | null>(null);
   const lastMarkedReadIssueIdRef = useRef<string | null>(null);
 
@@ -590,6 +591,14 @@ export function IssueDetail() {
     return () => closePanel();
   }, [issue]); // eslint-disable-line react-hooks/exhaustive-deps
 
+  useEffect(() => {
+    return () => {
+      if (copiedTimerRef.current !== null) {
+        clearTimeout(copiedTimerRef.current);
+      }
+    };
+  }, []);
+
   const copyIssueToClipboard = async () => {
     if (!issue) return;
     const decodeEntities = (text: string) => {
@@ -603,7 +612,13 @@ export function IssueDetail() {
     await navigator.clipboard.writeText(md);
     setCopied(true);
     pushToast({ title: "Copied to clipboard", tone: "success" });
-    setTimeout(() => setCopied(false), 2000);
+    if (copiedTimerRef.current !== null) {
+      clearTimeout(copiedTimerRef.current);
+    }
+    copiedTimerRef.current = setTimeout(() => {
+      setCopied(false);
+      copiedTimerRef.current = null;
+    }, 2000);
   };
 
   if (isLoading) return <p className="text-sm text-muted-foreground">Loading...</p>;