* Track the window focus/blur events. Leaving the tab while in a channel
now means you may still hear sound effects in that channel.
* Add a CORS JSON API /v1/statistics to get details from the server
about who is online. The CORSHosts whitelist in the settings.toml
limits domain access to the endpoint.
* Added a top panel to put your video controls in.
* Broadcaster can mute or unmute their own audio input.
* When viewing others' cams, buttons appear to control their video:
* Their username is displayed in the corner.
* Mute/unmute button to silence their audio.
* "X" button to close their camera.
* Button to show what viewers are currently watching your camera.
* Add an "About" page and config for app branding.
* Add dark theme CSS for prefers-dark browsers.
