[ready to merge] docs(flaky-tests): Setup steps + Validate sections

[samgutentag]

Summary

• Convert the ### Checklist + bulleted [ ] pattern to a Mintlify <Steps> block with linked-title <Step> children across all 42 framework and CI-provider get-started pages. Rename the heading to Setup steps and consolidate the surrounding prose into a single intro line.
• Add a ### Validate Your Uploads section to all 13 CI provider pages so the final Setup step has a real link target. GitHub Actions gets a GitHub-specific version (workflow / action logs / repo secrets); the other 12 share a generic version pointing at app.trunk.io and the Uploads + Tests tabs.

Why

Mintlify wasn't rendering GitHub-flavored task-list syntax cleanly — bullets and checkboxes were doubling up visually. <Steps> is the closest native Mintlify component for an ordered preview of section steps. It gives real numbered structure plus clickable jump-links to the matching section, which is what these "Checklist" sections were trying to be all along.

Notes

• <Step title="..." /> accepts a string only — markdown link syntax inside the prop renders as literal [text](url). To get a clickable title, pass JSX: title={<a href="#anchor">text</a>}.
• The 13 CI provider pages had an orphan "Validate your uploads in Trunk" step (no matching heading existed). The new Validate Your Uploads section gives them a real anchor target instead of leaving the step unlinked.

Test plan

• Preview a framework page (e.g. /flaky-tests/get-started/frameworks/cypress) — Setup steps renders as 4 numbered items, each title links to the matching section on the page.
• Preview /flaky-tests/get-started/ci-providers/github-actions — all 4 Setup steps link, including the new Validate Your Uploads anchor.
• Spot-check a generic CI page (e.g. circleci, gitlab) — Validate Your Uploads section renders correctly and the closing Tip block is still the page closer.
• Spot-check flaky-tests/get-started/frameworks/rspec/index — the <Info> callout below the Steps block is preserved.

[samgutentag]

Verification status (2026-05-19): live

Verified: pure docs change with no eng dependency. Ready to publish.

• Eng PR: none (docs-only)
• Flag: none
• Signals: pure docs reorganization (replaces "Checklist" pattern with Mintlify <Steps> blocks across 42 framework / CI provider pages; adds Validate Your Uploads section to 13 CI provider pages).