perf(client): cut needless polling for local users

- ConversationView: an ended session (SessionDetail, SessionReplay pass
  `ended`) polls its transcript every 60 s instead of 3 s and stops
  rescanning sub-agents; new_event, reconnect and show still fetch at once.
- Workspace: GET /api/run follows run-moving WS messages (lane run
  columns, session created/status change, runs_interrupted) with a 30 s
  fallback, instead of a blind 5 s poll.
- StatusBar: session counts re-read only when a session's
  status/waiting/archived state changes (60 s fallback); costs re-read at
  most every 30 s while work is happening and every 2 min otherwise.
- Dashboard recent activity: 60 s safety poll (was 10 s) plus remote
  import messages; WS still prepends new events.
- New lib/sessionChange.ts matcher with tests.

client/src/components/lanes/SessionReplay.tsx

@@ -132,7 +132,11 @@ export function SessionReplay({
         </div>
       )}
       <div className="min-h-0 flex-1 overflow-hidden">
-        <ConversationView sessionId={sessionId} fill />
+        <ConversationView
+          sessionId={sessionId}
+          fill
+          ended={!livePane && !!session && session.status !== "active"}
+        />
       </div>
       {livePane ? (
         <div