v3.15.0 — Reset owner link, board settings as a bottom sheet, dialog focus

A leaked owner link can now be taken back. No migrations.

Reset owner link

• Board settings → Owner link → Reset owner link. For a link pasted into the class group by mistake. It's confirmed first, then you get a new owner link, shown once on the "Save your owner link" screen. The old link stops working everywhere.
• Other browsers really lose access. Before this, owner access in a browser's session wasn't tied to the link. A browser that had used an old link stayed owner even after recovery changed the link. Owner sessions are now bound to the current link, so a reset or a recovery signs out every other browser on its next page load. The browser that made the change stays signed in.

Board settings on phones

• Board settings now rises from the bottom, only as tall as its content, like every other sheet. The board stays visible above it, and tapping there closes it. It moves up above the on-screen keyboard while you type a recovery email.
• Tablet and desktop keep the panel on the right.

Accessibility

• Dialogs on the board page and the start page, and Suggest, now move keyboard focus inside when they open, keep Tab within them, and return focus to the button that opened them when they close.
• Confirms open on Cancel, and screen readers announce their question and what will happen.
• The "Anyone with the link can add files" switch keeps focus while it saves, and the settings sections are headings.

Before you deploy

Nobody is signed out. Sessions from before this release are upgraded the first time they're used, so owners who never saved their link keep access. The catch: a browser that got owner access from a leaked link before this release is upgraded too, and keeps it until the owner resets the link. If an owner thinks their link leaked, Reset owner link is the fix.

220 tests.