fix: track value of inputs and textareas in shadow DOM

[TanbirRamim]

What

Fixes #1314. For an <input> or <textarea> inside a shadow root, setting .value after user.type() was not picked up, so the next user.type() appended to the old text (helloworld instead of world). The change event on blur was also never dispatched for these elements.

Why

The document-level focus and blur listeners in prepareDocument used event.target, which is retargeted to the shadow host, so the value interceptor was never installed on the actual element.

How

Both listeners now use event.composedPath()[0] to get the original target. I added tests for value tracking and the blur change event in tests/document/index.ts, plus the reported user.type() case in tests/utility/type.ts; all three fail before the change and pass after, and lint and typecheck are clean. Closed shadow roots still resolve to the host, same as before.

Checklist

• Documentation N/A
• Tests
• Ready to be merged

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[snowystinger]

The first three steps of the composedPath algorithm suggest this could be an empty array
https://dom.spec.whatwg.org/#dom-event-composedpath

one place this can happen is if a synthetic focus or blur is called. Some libraries do this to trigger known side effects, so I think we need to check the length and fall back to target if it's empty

[snowystinger]

I think these lines need to use getActiveElement instead?

[TanbirRamim]

Thanks, both changed. The focus and blur listeners now fall back to e.target when composedPath() is empty, and the element prepared up front comes from getActiveElement(document) so an already-focused element inside a shadow root is picked up too. I added a test that dispatches focus/blur events with an empty composed path, which was needed to keep branch coverage at 100%.