Commenting on mobile

Commenting on a mobile layout: the thread popover and composer place themselves to stay on-screen above the keyboard.

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The same commenting toolkit as the Commenting example, with forceMobile on the editor so the mobile layout shows on any screen size.

In mobile mode the thread popover and the new-comment composer position themselves relative to the pin and the visual viewport, rather than sitting at a fixed offset. They pick a side of the pin that keeps the whole panel on-screen, and ride up when the software keyboard shrinks the viewport instead of hiding behind it. Place a comment near an edge to see the placement adapt.

Drop forceMobile and the layout switches on the viewport width, the way it does on a real device.