add focusSendBoxInput method

[marclundgren]

Add ref-based focus control to Composer component to enable focus send box

Summary

This PR adds a ref prop to the Composer component that exposes a focusSendBoxInput() method, allowing parent components to programmatically focus the chat input field.

Changes

• Added ComposerRef type with focusSendBoxInput() method
• Converted Composer component to use forwardRef
• Created internal ComposerWithRef component that uses the existing useFocus hook
• Updated FullComposer to forward refs properly
• Exported ComposerRef type from all package entry points

Usage Example

import React, { useRef } from 'react';
import { Composer, ComposerRef } from 'botframework-webchat';

const MyApp: React.FC = () => {
  const webChatRef = useRef<ComposerRef>(null);
  const focusChatInput = () => {
    webChatRef.current?.focusSendBoxInput();
  };

  return (
    <div>
      <button onClick={focusChatInput}>Focus Chat Input</button>
      <Composer
        ref={webChatRef}
        directLine={yourDirectLine}
        // ... other props
      />
    </div>
  );
};

• I have added tests and executed them locally
• I have updated CHANGELOG.md
• I have updated documentation

Review Checklist

This section is for contributors to review your work.

• Accessibility reviewed (tab order, content readability, alt text, color contrast)
• Browser and platform compatibilities reviewed
• CSS styles reviewed (minimal rules, no z-index)
• Documents reviewed (docs, samples, live demo)
• Internationalization reviewed (strings, unit formatting)
• package.json and package-lock.json reviewed
• Security reviewed (no data URIs, check for nonce leak)
• Tests reviewed (coverage, legitimacy)

[beyackle2]

Normally I'd approve this, but I know William is very specific about the format of the changelog; fix that and I'll re-approve.

[beyackle2]

This should follow one of the changelog line templates above (e.g. link to an issue or your GH page)

[marclundgren]

Hi @beyackle2! 👋

I've updated the CHANGELOG.md entry to follow the proper format. The entry now includes:

• Author attribution: by [@marclundgren](https://github.com/marclundgren)
• PR reference: in PR [#5512](https://github.com/microsoft/BotFramework-WebChat/pull/5512)

The updated entry matches the format used by other entries in the changelog. The change has been committed and pushed.

Thanks for the feedback! 🙏

[OEvgeny]

How about moving composer upper in the tree and utilizing existing useFocus() hook?

The use-case seems can be solved in userland without the proposed modification.