Reset maxAtlasPages after tests that lower it

setMaxAtlasPages mutates a static that lives for the page's lifetime, so a
lowered cap silently leaked into every renderer built by later tests in the
same file (their GL texture and shader sampler arrays were sized at the tiny
cap, making tests order-dependent). Add resetMaxAtlasPages and call it in
afterEach wherever the cap is lowered on a shared page.

addons/addon-webgl/test/WebglReproExperiment.test.ts

@@ -14,7 +14,7 @@
  */
 import test, { expect } from '@playwright/test';
 import { ITestContext, createTestContext, openTerminal } from '../../../test/playwright/TestUtils';
-import { captureRowSignatures, expectSignatureMatches, getAtlasPageCount, loadWebglStrict, setMaxAtlasPages, writeAndWaitForRender } from '../../../test/playwright/RendererTestUtils';
+import { captureRowSignatures, expectSignatureMatches, getAtlasPageCount, loadWebglStrict, resetMaxAtlasPages, setMaxAtlasPages, writeAndWaitForRender } from '../../../test/playwright/RendererTestUtils';
 import { generateColoredAsciiFlood } from '../../../test/playwright/SyntheticTui';
 
 const HEADER = ' HEADER_REF_0123456789';
@@ -27,6 +27,9 @@ test.describe('single-terminal merge integrity (#322756 class)', () => {
   test.skip(({ browserName }) => browserName !== 'chromium');
   test.describe.configure({ timeout: 60000 });
 
+  // A lowered page cap must not leak into renderers built by later tests.
+  test.afterEach(async () => await resetMaxAtlasPages(ctx));
+
   test('pinned header renders identically across 30 merge-heavy body redraws', async () => {
     await openTerminal(ctx, { cols: 80, rows: 24 });
     await loadWebglStrict(ctx);