Replace && with ; in test:coverage so the client vitest run is not
short-circuited when the server run exits non-zero (e.g. threshold
violation or test failure). Without this the upload-artifact step
only ever sees coverage/server.
Also updates the stale CLAUDE.md comment that said server-only.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>