fix(core): wire aria-describedby and aria-busy on DateTimeInput time input

[bhamodi]

Summary

In packages/core/src/DateTimeInput/DateTimeInput.tsx the field's description, status message, and disabled-reason are collected into a single ariaDescribedBy string (around line 478), and the field's busy state into isBusy (line 444). The date input wires both: aria-describedby={ariaDescribedBy} (line 911) and aria-busy={isBusy || undefined} (line 916). The embedded time input (around lines 973-999) set aria-label, aria-required, aria-invalid, and aria-disabled — but neither aria-describedby nor aria-busy.

Both halves live under one Field label, so the description, status message, and disabled message describe the whole control. Because only the date input carried aria-describedby, a screen-reader user who tabbed into the time half lost access to all three, and never heard the field announced as busy during an async change. This is a WCAG 1.3.1 Info and Relationships gap for the time input.

The fix adds the same two attributes to the time input, reusing the existing ariaDescribedBy and isBusy values so the two halves stay in parity.

Changes

• packages/core/src/DateTimeInput/DateTimeInput.tsx: add aria-describedby={ariaDescribedBy} and aria-busy={isBusy || undefined} to the time <input>.
• packages/core/src/DateTimeInput/DateTimeInput.test.tsx: added tests asserting the time input's aria-describedby resolves to the description, the status message, and the disabled reason, plus aria-busy parity with the date input (set when isLoading, absent otherwise).

Test plan

• node_modules/.bin/vitest run --root . packages/core/src/DateTimeInput — 62 pass (was 58), including the 5 new tests.
• Confirmed failing-first: ran the new tests before the fix — the three aria-describedby tests and the aria-busy time-input test all failed (aria-describedby/aria-busy was null on the time input), proving they catch the gap.
• node_modules/.bin/tsc --project packages/core/tsconfig.json --noEmit — clean.
• node_modules/.bin/eslint packages/core/src/DateTimeInput/DateTimeInput.tsx packages/core/src/DateTimeInput/DateTimeInput.test.tsx — clean.

Notes

Found during a broader a11y audit of the DateTimeInput component. Scoped to these two attributes on the time input plus tests. DateTimeInput.doc.mjs doesn't document aria-describedby/aria-busy, so no doc change was needed.

[vercel]

@bhamodi is attempting to deploy a commit to the Meta Open Source Team on Vercel.

A member of the Team first needs to authorize it.