Fix user profile writes on postgres conflicts

backend/internal/service/auth_email_binding.go

@@ -277,7 +277,9 @@ func ensureBoundEmailAuthIdentityWithClient(
 		).
 		DoNothing().
 		Exec(ctx); err != nil {
-		return err
+		if !isSQLNoRowsError(err) {
+			return err
+		}
 	}
 
 	identity, err := client.AuthIdentity.Query().

backend/internal/service/auth_service.go

@@ -916,6 +916,11 @@ func (s *AuthService) ensureEmailAuthIdentity(ctx context.Context, user *User, s
 			).
 			DoNothing().
 			Exec(ctx); err != nil {
+			if isSQLNoRowsError(err) {
+				err = nil
+			}
+		}
+		if err != nil {
 			logger.LegacyPrintf("service.auth", "[Auth] Failed to ensure email auth identity: user_id=%d email=%s err=%v", user.ID, email, err)
 			return nil, false
 		}

backend/internal/service/sql_errors.go

@@ -0,0 +1,14 @@
+package service
+
+import (
+	"database/sql"
+	"errors"
+	"strings"
+)
+
+func isSQLNoRowsError(err error) bool {
+	if err == nil {
+		return false
+	}
+	return errors.Is(err, sql.ErrNoRows) || strings.Contains(err.Error(), "no rows in result set")
+}