Add CI accessibility testing guide documenting the WCAG 2.1 AA quality gate
that blocks releases on accessibility violations. Update main README to
reference the new documentation and clarify that accessibility tests are
a CI gate, not just local development tools.
This completes the accessibility quality gate requirement.
Covers Spaxel overview, realistic CSI capabilities, privacy framing, the
go.work multi-module repo layout, docker-compose quickstart with key env
vars, and pointers to docs/plan, docs/notes, docs/research, and the
dashboard README. Accurate to the current tree (image ronaldraygun/spaxel);
no secrets or host paths.
Co-Authored-By: Claude <noreply@anthropic.com>