refactor(net): converge live session state reset

tests/AcDream.Core.Tests/Combat/CombatStateTests.cs

@@ -141,4 +141,31 @@ public sealed class CombatStateTests
         Assert.Equal(0, state.TrackedTargetCount);
         Assert.Equal(CombatMode.NonCombat, state.CurrentMode);
     }
+
+    [Fact]
+    public void Clear_RetryRepublishesAndOneObserverCannotStarveAnother()
+    {
+        var state = new CombatState();
+        state.SetCombatMode(CombatMode.Melee);
+        bool fail = true;
+        int delivered = 0;
+        state.CombatModeChanged += _ =>
+        {
+            if (fail)
+            {
+                fail = false;
+                throw new InvalidOperationException("transient");
+            }
+        };
+        state.CombatModeChanged += mode =>
+        {
+            Assert.Equal(CombatMode.NonCombat, mode);
+            delivered++;
+        };
+
+        Assert.Throws<AggregateException>(state.Clear);
+        Assert.Equal(1, delivered);
+        state.Clear();
+        Assert.Equal(2, delivered);
+    }
 }