chore: release server-v1.0.64

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/internal/handler/auth.go

@@ -48,6 +48,9 @@ func (h *AuthHandler) Login(c *gin.Context) {
 			status = http.StatusTooManyRequests
 		} else if errors.Is(err, service.ErrPlatformNotAllowed) {
 			status = http.StatusForbidden
+		} else if errors.Is(err, service.ErrDeviceLimitReached) {
+			c.JSON(http.StatusConflict, gin.H{"error": err.Error(), "code": "DEVICE_LIMIT"})
+			return
 		}
 		c.JSON(status, gin.H{"error": err.Error()})
 		return