Accessibility: complete a VoiceOver walkthrough of the playground and HTML report

[ChelseaKR]

Goal

Complete a manual VoiceOver and keyboard walkthrough of the browser playground
and one generated HTML report.

Scope

• Browser playground at https://chelseakr.github.io/tods-validate/
• A generated report from a synthetic fixture
• macOS VoiceOver with browser and operating-system versions recorded

Tasks

• Reach every control using the keyboard.
• Select a synthetic feed and run validation.
• Locate the summary and navigate findings by heading or landmark.
• Confirm that error, warning, and informational states do not depend on color.
• Confirm that the report remains understandable when read linearly.

Done when

• Results are recorded in a dated document under docs/a11y/.
• Each blocked or confusing task has a focused follow-up issue.
• The README and conformance ledger are updated only to the level supported
  by the recorded evidence.

Automated checks are not a substitute for this task.