Rifiuta il riuso della password attuale in cambio e reset.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/services/users/change_password.rb

@@ -31,6 +31,10 @@ module Users
         return Result.new(ok?: false, error: code == :blank ? :too_short : code)
       end
 
+      if PasswordComplexity.same_as_current?(@user, @password)
+        return Result.new(ok?: false, error: :same_as_current)
+      end
+
       unless @user.update(password: @password)
         complexity_error = @user.errors.details[:password]&.any? { |d| d[:error] == :complexity }
         return Result.new(ok?: false, error: complexity_error ? :too_weak : :too_short)