#22807: fix: parameterize magic numbers in ensureA2uiReady (issue #22745)

Fixes #22745. Recreating PR 22785 from a clean branch to resolve bot closure. <!-- greptile_comment --> <h3>Greptile Summary</h3> Extracted hardcoded magic numbers (50 retries, 120ms delay) from `ensureA2uiReady` into configurable parameters with sensible defaults, addressing issue #22745. <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk - The change is simple, well-scoped, and backward-compatible. It adds optional parameters with sensible defaults that match the previous hardcoded values. All existing call sites remain functional without modification. No logical errors, security issues, or runtime risks identified. - No files require special attention _{Last reviewed commit: 498d597} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->