sanity-visual-regression

Add, review, and maintain Chromatic visual regression coverage in the Sanity monorepo via dev/storybook stories, the vitest browser-mode suite, and Playwright e2e snapshots. Use when adding visual test coverage, writing stories, reviewing Chromatic diffs, working on the styled-components to vanilla-extract or @sanity/ui to ui5 migrations, or when a PR needs visual regression protection.