* Use opInflightSince to measure unsaved doc time
* Use performance.now() for lastAcked timestamp
* Use inflightOpCreatedAt
* Increase MAX_UNSAVED_ALERT_SECONDS to 15
* Increase MAX_UNSAVED_SECONDS to 30
* Increase FATAL_OP_TIMEOUT to 45000
* Convert "Connection lost" modal to a notification
GitOrigin-RevId: 2d4233723620fd03ce6d6c5795c48c33c0b2f92c
* Notify about unsaved changes
* Move system message components and types to shared folder
* Add system messages component
GitOrigin-RevId: ab81a24888847bd9a8a390fd1af6b58f471f7a4b