Studio view uses minified JS.
Studio save errors display in the UI.
TIM-346: Server-and-client-side size validation

TODO:
 * @talbs .message__content is styled very badly everywhere
 * Sizes are way too big, currently defaulting to 1MB for API and 256KB
   for js
 * Sizes are configured in too many places, when they should come in via
   settings or something

WIP: Adding spec tests for javascript

Confirming that too-large input fails successfully, and that removing the
validations from the js causes failing fails.

WIP fixing the error message dialog