Multi-user servers: email and invite codes at sign-up and sign-in

Create account takes an email and an invite or setup code (none with open
sign-up), joins servers that already have accounts, and Settings shows the
account email (admins manage people from the web vault).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src-tauri/src/main.rs

@@ -154,17 +154,18 @@ fn state(app: State<'_, App>) -> AppState {
 
 // Argon2id takes ~0.5 s, so these run as async commands off the main thread.
 
-/// "Create a new account": a new vault here, registered with a fresh server using its setup code.
+/// "Create a new account": a new vault here, registered with the server using its setup code or an invite.
 #[tauri::command]
 async fn create_account(
     app: State<'_, App>,
     server_url: String,
     pins: String,
     setup_code: String,
+    email: String,
     master_password: String,
 ) -> CmdResult<String> {
     let master_password = Zeroizing::new(master_password);
-    let sk = app.sync.create_account(&server_url, sync::parse_pins(&pins), &setup_code, master_password).await;
+    let sk = app.sync.create_account(&server_url, sync::parse_pins(&pins), &setup_code, &email, master_password).await;
     app.activity.touch();
     sk.map(|s| s.to_string())
 }
@@ -378,8 +379,8 @@ async fn server_setup_open(app: State<'_, App>) -> CmdResult<bool> {
 }
 
 #[tauri::command]
-async fn register_server(app: State<'_, App>, setup_code: String) -> CmdResult<()> {
-    app.sync.register(&setup_code).await
+async fn register_server(app: State<'_, App>, setup_code: String, email: String) -> CmdResult<()> {
+    app.sync.register(&setup_code, &email).await
 }
 
 #[tauri::command]