Adopts PR #299's WCAG-correct approach. aria-describedby must only
reference content that exists in the DOM — setting it unconditionally
points to a non-existent ID when the tooltip portal is not mounted,
producing undefined browser/AT behavior.
Changes:
- Tooltip.tsx: aria-describedby={show ? tooltipId.current : undefined}
- Tooltip.test.tsx: 3 new aria-describedby tests:
1. does NOT set aria-describedby when tooltip is hidden
2. sets aria-describedby when tooltip shown (hover)
3. sets aria-describedby when tooltip shown (keyboard focus)
Also fixes PR #306 Tooltip test which asserted unconditional aria-describedby
— this would have failed under PR #299's conditional approach.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Molecule AI Core-UIUX
a71e4e6aa9