test(site): isolate visual baselines from canvas

Author: ilyar

docs/visual-acceptance.md

@@ -10,6 +10,7 @@ The baseline covers:
 - focused navbar states, including the scrolled blur layer;
 - focused glass surfaces in normal and hover states;
 - CSS guards for active `backdrop-filter` and translucent glass backgrounds;
+- stable page baselines with the non-deterministic WebGL canvas hidden;
 - real scroll/anchor positions rather than isolated components.
 
 There is also a non-baseline animation smoke test. It runs with reduced motion

tests/acceptance/design-baseline.spec.ts

@@ -47,9 +47,11 @@ async function waitForScrolledNavbarEffect(page: Page) {
 }
 
 async function waitForVisualReady(page: Page) {
+  await page.addStyleTag({
+    content: 'canvas { visibility: hidden !important; }',
+  });
   await page.evaluate(() => document.fonts.ready);
-  await page.locator('canvas').first().waitFor({ state: 'attached', timeout: 3_000 }).catch(() => undefined);
-  await page.waitForTimeout(500);
+  await page.waitForTimeout(300);
 }
 
 const states = [