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/pages/ProjectDetail.tsx

@@ -91,7 +91,7 @@ export function ProjectDetail() {
               {projectIssues.map((issue) => (
                 <EntityRow
                   key={issue.id}
-                  identifier={issue.id.slice(0, 8)}
+                  identifier={issue.identifier ?? issue.id.slice(0, 8)}
                   title={issue.title}
                   trailing={<StatusBadge status={issue.status} />}
                 />