fix(sessions): centralize global polling

packages/ui/src/hooks/useGlobalSessionsPolling.test.ts

@@ -0,0 +1,39 @@
+import { describe, expect, test } from 'bun:test';
+import {
+  GLOBAL_SESSIONS_REFRESH_INTERVAL_MS,
+  startGlobalSessionsPolling,
+} from './useGlobalSessionsPolling';
+
+describe('global sessions polling lifecycle', () => {
+  test('loads immediately, owns one interval, and clears it on disposal', () => {
+    let initialLoads = 0;
+    let refreshes = 0;
+    let scheduledCallback = () => {};
+    let scheduledIntervals = 0;
+    let scheduledDelay = 0;
+    let clearedIntervalId: number | null = null;
+
+    const dispose = startGlobalSessionsPolling(
+      () => { initialLoads += 1; },
+      () => { refreshes += 1; },
+      (callback, delay) => {
+        scheduledIntervals += 1;
+        scheduledCallback = callback;
+        scheduledDelay = delay;
+        return 42;
+      },
+      (intervalId) => { clearedIntervalId = intervalId; },
+    );
+
+    expect(initialLoads).toBe(1);
+    expect(refreshes).toBe(0);
+    expect(scheduledIntervals).toBe(1);
+    expect(scheduledDelay).toBe(GLOBAL_SESSIONS_REFRESH_INTERVAL_MS);
+
+    scheduledCallback();
+    expect(refreshes).toBe(1);
+
+    dispose();
+    expect(clearedIntervalId).toBe(42);
+  });
+});