UI: Identity component, LiveRunWidget, issue identifiers, and UX improvements

Add Identity component (avatar + name) used across agent/issue displays. Add
LiveRunWidget for real-time streaming of active heartbeat runs on issue detail
pages via WebSocket. Display issue identifiers (PAP-42) instead of UUID
fragments throughout Issues, Inbox, CommandPalette, and detail pages.
Enhance CommentThread with re-open checkbox, Cmd+Enter submit, sorted display,
and run linking. Improve Activity page with richer formatting and filtering.
Update Dashboard with live metrics. Add reports-to agent link in AgentProperties.
Various small fixes: StatusIcon centering, CopyText ref init, agent detail
run-issue cross-links.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/components/CopyText.tsx

@@ -12,7 +12,7 @@ interface CopyTextProps {
 
 export function CopyText({ text, children, className, copiedLabel = "Copied!" }: CopyTextProps) {
   const [visible, setVisible] = useState(false);
-  const timerRef = useRef<ReturnType<typeof setTimeout>>();
+  const timerRef = useRef<ReturnType<typeof setTimeout>>(undefined);
   const triggerRef = useRef<HTMLButtonElement>(null);
 
   const handleClick = useCallback(() => {