Add sync status in the browser client

Hi,

After months of smooth sailing, SB Sync suddenly stopped working. I only noticed after opening SB Desktop and seeing the sync status had turned red.

After some debugging, I found that the issue was related to my Tailscale setup.

The problem is that I kept using the browser client without realizing that sync had stopped. The next day, I was surprised that I didn't have any conflicts, and I wouldn't have noticed the issue if I hadn't opened SB Desktop.

The green/red sync indicator is really helpful. I think it would be great to have the same indicator in the browser client too.

The top bar should turn entirely yellow when sync is failing, was that not visible, did it not happen?

I haven't been able to reproduce it since, but I had an instance where a file didn't sync but there was no indication for it