Update dimension checking to avoid .id- selectors
Fix time separator using previous hour.
Use user-local timezone for all timestamps.

This makes time separators client-side only since we won't know
server-side what time zone they're in and some time zones aren't whole
hours off of UTC which would cause the time separators to happen in
different places.
Only allow desktop notifications if the socket is available.
Add button and discrete permission for closing stream.