feat(Select): add position prop & align-item

[maxffarrell]

Not sure that the popover behavior is correct, implemented with Codex so it may or may not be useful as a starting point

[changeset-bot]

⚠️ No Changeset found

Latest commit: a3262fe

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[github-actions]

built with Refined Cloudflare Pages Action

⚡ Cloudflare Pages Deployment

Name	Status	Preview	Last Commit
bits-ui	✅ Ready (View Log)	Visit Preview	a3262fe

[huntabyte]

Suggested change

	If you want Radix-style item alignment, set `position="item-aligned"`:
	If you want MacOS native style item alignment, set `position="item-aligned"`:

[huntabyte]

CleanShot.2026-02-19.at.14.55.28.mp4

This is close, but it needs to account for the scroll buttons potentially being there. I would expect clicking on the trigger and then again quickly without moving my mouse it would hit the selected item and not the scroll button.

I will give this a more thorough review when I have some time, as I see some things in the constructor etc that look like they are causing extra work even when the position is not item-aligned.

Thank you!