* Added toggle chat button to navigation header
* new `useBrowserWindow` hook to work with browser title and focus
* react2angular chat toggle button plumbing
GitOrigin-RevId: 4380f1db9c7cc9a25bfb8d7a33e18d61b1d32993
* Fixed unread message count in react chat
The problem was caused by ChatStore being instantiated multiple times on each `useRef` call, plus also incorrectly cleaned-up, since it should be calling `socket.removeListener` instead of `socket.off` on effect destroy.
* deferred loading messages until chat is opened
GitOrigin-RevId: b990cd06cea6630472b0911b56219766717aaff6
