Prefer the best available YouTube thumbnail, fall back cleanly when high-resolution images are unavailable, and keep the React Doctor PR gate scoped to newly introduced issues.
Adds the official react-doctor GitHub Action (millionco/react-doctor@v1),
which posts inline review comments + a sticky summary for issues a PR
INTRODUCES (diffed against the merge-base) -- more visible than the
previous CLI '--annotations' markers.
Removes the now-redundant react-doctor steps from ci.yml (the
detect-changes/diff-annotations/skip steps and the push-time full scan)
so react-doctor runs once per PR, not twice. It reads doctor.config.jsonc,
so the React-Compiler rules we don't enforce stay suppressed.
