Issue number: resolves #30561

What is the current behavior?

When an ion-select with interface="popover" or interface="modal" is opened with the keyboard, pressing Enter on a focused option doesn't commit the value or dismiss the overlay. Only Space works. The onKeyUp handlers in select-popover.tsx and select-modal.tsx only checked for ' ', despite the comment claiming Enter was supported, and ion-radio-group's arrow-key handler never committed the focused value on Enter the way native <select> does.

What is the new behavior?

Pressing Enter on a focused option in the popover or modal interface now commits that option as the select's value and dismisses the overlay, matching Space and native <select> behavior. radio-group.tsx gains an Enter branch inside its select-interface arrow-key handler that sets value to the focused radio and emits ionChange when it differs from the previous value. select-popover.tsx and select-modal.tsx track the onKeyDown target so onKeyUp only dismisses when the Enter press started on the same option. That guard stops a held Enter on the triggering ion-select from re-firing inside the just-opened overlay and auto-dismissing it. The !ev.repeat check on keydown covers the same case for the radio-group commit.

Does this introduce a breaking change?

• Yes
• No

Other information

The keydown/keyup target-matching pattern is the same trick the browser uses to avoid firing a click when keydown and keyup happen on different elements. It's needed here because Enter on the ion-select trigger opens the overlay on keydown, and without the guard the corresponding keyup (now inside the overlay) would immediately commit and dismiss.

Preview page:

• select / basic