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/lib/sessionChange.ts

@@ -0,0 +1,32 @@
+/**
+ * @file sessionChange.ts
+ * @description `session_created` / `session_updated` matcher for live-refresh
+ * callers that care about only a few session columns. A session row is
+ * re-broadcast on nearly every hook (last activity, name, tokens…), so
+ * matching the bare message types made every such frame refetch; this one
+ * fires on a new session, or when the chosen key of a session actually
+ * changed. Each call keeps its own memory of the keys it has seen.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+import type { Session, WSMessage } from "./types";
+
+/** The columns that move a session between the active / waiting / archived counts. */
+export const sessionStateKeyOf = (s: Partial<Session>): string =>
+  `${s.status}:${s.awaiting_input_since ? 1 : 0}:${s.archived_at ? 1 : 0}`;
+
+export function sessionChangeMatcher(
+  keyOf: (s: Partial<Session>) => string = sessionStateKeyOf
+): (msg: WSMessage) => boolean {
+  const seen = new Map<string, string>();
+  return (msg) => {
+    if (msg.type !== "session_created" && msg.type !== "session_updated") return false;
+    const s = msg.data as Partial<Session> | undefined;
+    // A frame we cannot key is taken as a change: refetching is the safe side.
+    if (!s || typeof s.id !== "string") return true;
+    const key = keyOf(s);
+    if (msg.type === "session_updated" && seen.get(s.id) === key) return false;
+    seen.set(s.id, key);
+    return true;
+  };
+}