feat(localize): leave the editor once the accepted boxes land

[Chouffe]

What

Confirming the localize editor's Accept boxes popover — with Enter or its own button — now closes the editor and returns to the object's cockpit page (/localize/:seq/object/:lane).

Why

Accepting the remainder settles every frame of the object, so the editor has nothing left to show. It stayed open anyway, and the annotator had to press Escape to get back to a cockpit that had already moved on without them.

How

LocalizeObjectEditor's onAcceptRemaining takes an optional onAccepted callback; both confirm paths pass the editor's own close, so the exit runs the existing shrink-back-into-the-grid animation rather than a hard unmount. LocalizeAlertPage fires that callback from the quick-accept mutation's onSuccess.

Closing on the write rather than on the gesture is deliberate: a failed accept leaves the object unfinished, so the editor stays open with its "Failed to accept boxes" toast still about the object in front of you.

The rail's copy of the same popover passes no callback and is unchanged — there is no editor to close there.

Two holes the first commit opened, and their fixes

Handing a close to the page makes it callable long after the gesture that armed it. Two consequences, each its own commit:

• Late callback after the editor is gone. Accept, then leave by another door — browser Back, which keeps the cockpit page (and its mutation) mounted — and the close ran on an unmounted editor, navigating the annotator back to where they had just left. mountedRef already guards the exit animation's finish handler for this reason; the guard now sits on the whole request.
• Close frozen at gesture time. requestClose closes over the open frame, and nothing stops an ArrowRight while the bulk upsert is in flight. The editor would shrink into the cell of a frame already left, possibly one scrolled out of view. A ref resolves the callback to the current close instead — the same trick clearRef uses to keep the keyboard handler from re-binding.

Testing

Editor level: Enter-confirm and click-confirm each close once the callback fires; a callback arriving after unmount does nothing; the close targets the frame the annotator is on rather than the one they accepted from.

Page level (LocalizeAlertPage.test.tsx, "accept popover → from the editor"): the editor closes to /localize/101/object/102 once the write lands, and stays on screen with its failure toast when the bulk write rejects.

That page pair exists because an earlier editor-level "stays put" test was vacuous — the failure semantics live in the page's { onSuccess }. Swapping it for { onSettled }, which would close on a failed accept and bury the error toast, left the entire suite green. Both page tests were watched failing against that mutant before being kept; the redundant editor test is gone.

Full frontend suite 1503/1503, type-check, lint and format:check clean.

Caveat: jsdom has no Web Animations API, so most editor tests exercise the non-animated fallback; the frame-targeting test drives the suite's existing WAAPI stub. The real animated close was verified by hand in the browser.