Keep TurnStatus disclosures accessible and activity announcements quiet

[Maya-Kid]

With children, TurnStatus renders a button with role="status", hiding its disclosure from assistive technology's button navigation. The live region also includes the ticking timer and animated token count.

Keep the native button role and give it a stable activity name. Announce activity changes through a separate screen-reader-only status region; omitted or blank labels fall back to the activity name. The visible counters and Enter/Space disclosure behavior stay the same.

This is the standalone accessibility follow-up separated from #30 after review.

Validation:

• npm run docs, npm run typecheck, and npm run build pass.

• Chrome 155, light and dark: 389/389 examples mounted, 0 failed, no browser errors.

• Accessibility-tree checks cover the native button role, stable names, omitted/blank/localized labels, activity changes, and the status without children. Enter and Space expand/collapse the details.

• Changing tokens from 42 to 4,242 and advancing the timer produces no mutations in the activity status region. Checked the closed and expanded views in both themes.

• Every commit is signed off (git commit -s)

• npm run typecheck and npm run build pass

• /dev/examples reports 0 failed

• What the change touches was looked at in both themes, open states included

• The component has its example in src/examples/ and its page in content/solid/