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/__tests__/sessionChange.test.ts

@@ -0,0 +1,34 @@
+/**
+ * @file sessionChange.test.ts
+ * @description Unit tests for `sessionChangeMatcher`: fires on a new session
+ * and on a change of the keyed columns, never on a re-broadcast that moved none.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+import { describe, expect, it } from "vitest";
+import { sessionChangeMatcher } from "../sessionChange";
+import type { WSMessage } from "../types";
+
+const msg = (type: string, data: unknown) => ({ type, data, timestamp: "" }) as WSMessage;
+
+describe("sessionChangeMatcher", () => {
+  it("fires on a new session and on a state change, not on a same-state re-broadcast", () => {
+    const m = sessionChangeMatcher();
+    expect(m(msg("session_created", { id: "a", status: "active" }))).toBe(true);
+    expect(m(msg("session_updated", { id: "a", status: "active", name: "x" }))).toBe(false);
+    expect(
+      m(msg("session_updated", { id: "a", status: "active", awaiting_input_since: "t" }))
+    ).toBe(true);
+    expect(m(msg("session_updated", { id: "a", status: "completed" }))).toBe(true);
+    expect(m(msg("session_updated", { id: "a", status: "completed", archived_at: "t" }))).toBe(
+      true
+    );
+  });
+
+  it("takes an unseen or unkeyable session as a change, and ignores other types", () => {
+    const m = sessionChangeMatcher();
+    expect(m(msg("session_updated", { id: "b", status: "active" }))).toBe(true);
+    expect(m(msg("session_updated", null))).toBe(true);
+    expect(m(msg("new_event", { session_id: "b" }))).toBe(false);
+  });
+});