Since Storybook 10.3, @storybook/addon-vitest provisions the preview
annotations itself — and *skips* doing so when it finds a setup file
calling setProjectAnnotations. So .storybook/vitest.setup.ts was not
merely redundant, it was actively opting the project out of the
automatic path, which the addon printed a notice about on every run.
Remove the file and the `setupFiles` entry from the `storybook` vitest
project.
A green suite doesn't prove the automatic provisioning works: without
the preview annotations, stories would render outside MantineProvider
and without App.css, and would very likely still pass. Add
src/test/PreviewAnnotations.stories.tsx, which asserts from a play
function that the Mantine theme variables and the App.css tokens are
actually present in the rendered document, so an unthemed render fails
loudly. Verified by emptying `decorators` in preview.tsx and confirming
the story goes red.
The a11y addon's axe runner can't be introspected from a play function,
so it was checked out-of-band: a story with a real violation turned the
suite red with the setup file already removed, confirming
@storybook/addon-a11y/preview is applied automatically.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0119LaPQ3v4NyBK3ZTdM9j84
ca70a7cfa7