Complete screen-reader accessibility acceptance #6

Automated axe checks passed, but human assistive-technology acceptance is pending. Follow docs/DEVELOPMENT.md.

• VoiceOver/Safari on macOS and iOS: record platform/version.
• NVDA with Firefox or Chrome on Windows: record platform/version.
• Verify trigger name/expanded state, named non-modal region, grouped controls, pressed states, stepper announcements and hidden-panel exclusion.
• Verify keyboard order, visible focus, Escape/Close return focus, reset announcements and route changes.
• Record findings and fix confirmed defects with regressions before sign-off.

Acceptance: reproducible human results in PROJECT_STATUS.md; no unresolved critical accessibility defect. Do not claim WCAG certification from automated results.

References: roadmap, development/acceptance guide.