v2.0.0-alpha.14

While this is an alpha release, new servers should use this rather than an older "stable" version.

Bugfixes:

• Fix preview media dialog backdrop size.
• Show preview button in history when not logged in.
• Tweak TextField outlines.

Internal:

• Use react-async-hook for async operations. (#2537)
• Setup chat commands in a more declarative way. (#2539)
• Mount dialogs as MUI intends. (#2540)