Add test-screenshots to gitignore

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

.gitignore

@@ -48,3 +48,6 @@ docs/.vitepress/cache
 apps/site/.next
 apps/site/.map.ts
 apps/site/.source
+
+# Test artifacts
+test-screenshots