Multi-account switching in Webmail

Multi-account switching is now live in Webmail. You can add all your mailboxes and switch between them straight from the profile menu, eliminating the need to log out and back in. Each account keeps its own session, so if one expires, you only need to sign back into that specific account. Each mailbox also has its own URL prefix (/0, /1, /2, etc.), allowing you to bookmark or pin tabs directly to the mailbox you want to access.