Misc. improvements to collaborative text controls and text-editor example application

[Josmithr]

• Removes the hardcoded headers from above exported text controls in react and quill-react - this isn't something we should be exporting as a part of our library. Users can add their own headings as needed.
• Updates exported text controls to ensure their entire editor space is clickable and causes the editor to be selected (previously, you could only accomplish this by clicking on a line that contained text, or the first line only if empty).
• Updates quill-based editor components to perform necessary cleanup on unmount.

Also updates the text-editor app to display all 3 editors at once, rather than only one at a time. Each is displayed as a collapsable card.

[Copilot]

Pull request overview

This PR refines the collaborative text editor controls and updates the text-editor example to better demonstrate multiple editor implementations side-by-side.

Changes:

• Removed hardcoded <h2> headings from exported editor views (React textarea, Quill plain, Quill formatted).
• Improved click-to-focus behavior so clicking the editor container focuses the underlying editor (and added cursor: text where applicable).
• Updated the text-editor example to show all three editor variants simultaneously per user, using collapsible cards.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
packages/framework/react/src/text/plain/plainTextView.tsx	Removes hardcoded heading; adds container click-to-focus for the textarea.
packages/framework/quill-react/src/plain/quillView.tsx	Removes hardcoded heading; adds container click-to-focus and text cursor styling.
packages/framework/quill-react/src/formatted/quillFormattedView.tsx	Removes hardcoded heading; adds container click-to-focus and text cursor styling.
examples/data-objects/text-editor/src/app.tsx	Reworks example layout to render all editors at once with collapsible cards per user.

[brrichards]

Left a small nit, but changes look good to me!