docs: expand accessibility props in README

[iamdarshshah]

Summary

• Splits the catch-all "Accessibility attributes" table row into four individual named rows (role, tabIndex, id, aria-*) consistent with the rest of the props table
• Adds a dedicated Accessibility section with two usage examples showing aria-label and aria-labelledby patterns

Context

Companion to #432, which adds the accessibility props to the component. The README in that PR used a single grouped row which would not be found by someone scanning the table for role or tabIndex by name, and had no usage guidance for consumers implementing screen reader support for the first time.

[github-actions]

Size Change: 0 B

Total Size: 9.51 kB

ℹ️ View Unchanged

Filename	Size
dist/index.es.js	4.73 kB
dist/index.js	4.78 kB

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.87%. Comparing base (dc9f7f4) to head (cccf1d6).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #433   +/-   ##
=======================================
  Coverage   95.87%   95.87%           
=======================================
  Files           4        4           
  Lines         194      194           
  Branches       65       65           
=======================================
  Hits          186      186           
  Misses          4        4           
  Partials        4        4           

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