ChatUserNames n'etait jamais alimente (relique d'un SetUserName disparu),
ce qui faisait lever KeyNotFoundException a chaque connexion SignalR et
fermait immediatement la connexion cote client ("Déconnecté (The server
closed the connection...)" dans PostIt).
- IConnexionManager.OnConnected prend desormais le userName en parametre
- HubConnectionManager.OnConnected alimente ChatUserNames et ChatCxIds
- ChatHub.OnConnectedAsync passe le userName resolu depuis les claims
Inclut aussi les changements PostIt lies (bandeau de statut avec
commande d'action, handlers Reconnecting/Reconnected/Closed).
Narrow ISmtpClient to the four operations MailSender actually uses,
behind a Yavsc.Interfaces.ISmtpClientFactory. Production wires
MailKitSmtpClient (SmtpClientFactory); tests wire a recording fake
(RecordingSmtpClientFactory). The fake is pre-registered in
WebServerFixture so SMTP calls are short-circuited; the EMailling
test now asserts the Connect -> Authenticate -> Send -> Disconnect
sequence. Yavsc.Abstract stays free of MailKit/MimeKit.
