Show a bare dash on ownerless school cards.

The design asked for the owner name or an em dash; wrapping the dash in the Owner template produced Хозяин: —. Low-speed clock tests now cover x1/2 and x2 as well as x1.

tests/HSchool.Simulation.Tests/ClockTempoTests.cs

@@ -23,18 +23,21 @@ public class ClockTempoTests
         Assert.Equal(1d, school.LastHeavyGameMinutes);
     }
 
-    [Fact]
-    public void AtX1_EveryImpulseRunsHeavySystems()
+    [Theory]
+    [InlineData(0, 0.5)]
+    [InlineData(1, 1d)]
+    [InlineData(2, 2d)]
+    public void LowSpeed_EveryImpulseRunsHeavySystems(int speedIndex, double expectedMinutes)
     {
         using var school = School.Create(1, "Каждый импульс", Start);
-        school.Clock.SpeedIndex = 1;
+        school.Clock.SpeedIndex = speedIndex;
 
         for (var i = 0; i < 20; i++)
         {
             school.Tick(OneTwentiethOfASecond, GameMinutesPerRealSecond);
         }
 
-        Assert.Equal(Start.AddMinutes(1), school.Clock.Time);
+        Assert.Equal(Start.AddMinutes(expectedMinutes), school.Clock.Time);
         Assert.Equal(20, school.HeavySystemsInvocations);
     }