perf(web): batch dashboard tile hydration

apps/web/src/lib/client/dashboard-refresh.test.ts

@@ -9,6 +9,7 @@ import {
   createDashboardTileBackoff,
   createDashboardRequestAborter,
   runDashboardHydrationQueue,
+  runDashboardHydrationBatchQueue,
   runViewportAwareDashboardHydrationQueue,
   shouldPauseDashboardRefresh,
   splitDashboardHydrationItemsByVisibility,
@@ -121,6 +122,25 @@ describe("dashboard refresh lifecycle", () => {
     expect(maxActive).toBe(2);
   });
 
+  test("hydrates queued work in fixed-size batches", async () => {
+    const batches: number[][] = [];
+
+    await runDashboardHydrationBatchQueue({
+      batchSize: 3,
+      hydrateBatch: (items) => {
+        batches.push(items);
+      },
+      items: [1, 2, 3, 4, 5, 6, 7],
+      signal: new AbortController().signal,
+    });
+
+    expect(batches).toEqual([
+      [1, 2, 3],
+      [4, 5, 6],
+      [7],
+    ]);
+  });
+
   test("hydrates visible items before deferred items and waits for idle", async () => {
     const calls: string[] = [];
     const idleReleases: Array<() => void> = [];