Store the dialog opener with useRef

[coderabbitai]

Summary

Replace the unused useState setter for the dialog opener with a useRef.

Required changes

• Store document.activeElement as the dialog opener in a ref.
• Preserve focus return and cleanup behavior.

Affected areas

• use-dialog-focus.ts

Acceptance criteria

• The opener is tracked without an unused state setter.
• Dialog close still returns focus to the opener.

Source

• Review comment: Feature/mutations #36 (comment)
• Pull request: Feature/mutations #36
• Requested by: @Alejandroq12

[coderabbitai]

Technical note

Use a ref for the opener because restoring focus needs a mutable value but does not need a render. Capture the element before focus moves into the dialog. On cleanup, call .focus() only when the saved element is still an HTMLElement and remains connected.

Reference: React: Referencing values with refs

[coderabbitai]

Engineering note

Use useRef for a value that must persist between renders but must not trigger a render. Capture the opener before the dialog moves focus. On close, restore focus only if the stored element is still connected to the document.

Read: React: useRef