[client] Tolerate already-deleted peer on profile logout, clear stale email

logoutFromProfile failed hard when the management server returned NotFound
(peer already deleted from the dashboard), blocking both profile logout and
profile removal. Treat NotFound as success — the peer is already gone, so
deregistering it is already satisfied.

Also drop the user-side per-profile state file on logout. The account email is
sourced from <profile>.state.json (written by the CLI after SSO login), which
the root daemon can't reach, so logout left a stale email showing in the UI.
Connection.Logout now removes it from the UI process after a successful logout;
the next SSO login recreates it.

client/internal/profilemanager/state.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"os"
 	"path/filepath"
 
 	"github.com/netbirdio/netbird/util"
@@ -59,3 +60,22 @@ func (pm *ProfileManager) SetActiveProfileState(state *ProfileState) error {
 
 	return nil
 }
+
+// RemoveProfileState deletes the per-profile state file (which holds the
+// account email used for the SSO login hint and the UI display). Called after
+// a successful logout so a logged-out profile no longer shows a stale account
+// email. The state file only stores the email, so deleting it is equivalent to
+// clearing it; the next SSO login recreates it. A missing file is not an error.
+func (pm *ProfileManager) RemoveProfileState(profileName string) error {
+	configDir, err := getConfigDir()
+	if err != nil {
+		return fmt.Errorf("get config directory: %w", err)
+	}
+
+	stateFile := filepath.Join(configDir, profileName+".state.json")
+	if err := os.Remove(stateFile); err != nil && !os.IsNotExist(err) {
+		return fmt.Errorf("remove profile state: %w", err)
+	}
+
+	return nil
+}