fix(ui): expose Input error state to assistive technology

[thariq122]

What & why

This PR improves the accessibility of the Input component by exposing validation errors to assistive technologies.

Closes #35

Changes

• Added stable IDs using useId()
• Linked the input to its error message using aria-describedby
• Added aria-invalid when validation errors exist
• Added role="alert" to the error message
• Preserved the existing forwardRef API

Checklist

• Focused change with a clear description
• Ran format / lint / tests (see README)
• Updated docs or CHANGELOG if relevant
• Linked any related issue (Closes Input component renders an error message that is never linked to the field #35)

[github-actions]

Welcome, @thariq122, and thanks for your first pull request to agent-postmortem.

A quick look at CONTRIBUTING.md covers how things are set up and run here.

I'll review this shortly. Ask anything in the thread if something is unclear.

[royalpinto007]

Excellent work @thariq122, this is exactly right.

You went past the issue: useId with a caller override, aria-invalid only when there is an error, aria-describedby that merges an existing one instead of clobbering it, role="alert" on the message, and aria-hidden on the decorative prefix and suffix. That last one matters, screen readers were announcing those as content.

All checks green. Merging. A star is appreciated if this was fun, and there are more open issues whenever you want another.

[github-actions]

This is in, @thariq122. Really appreciate it.

Good, focused change. Exactly the kind of thing agent-postmortem needs.

If agent-postmortem is useful to you, a star goes a long way.

Happy to see more from you whenever you have the time.