NEO-93: Fix delta cap LastAdvancedUtc to preserve gradual catch-up.

When simulation is capped, advance LastAdvancedUtc to windowEnd instead
of nowUtc so subsequent polls do not burst through missed NPC cycles.

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

docs/plans/NEO-93-implementation-plan.md

@@ -61,7 +61,7 @@
 - Holder-only idle→aggro sync from **`IThreatStateStore`**; no proximity auto-aggro.
 - **`attack_execute`** chains instantly to **`recover`** within the same advance step (no player damage — NEO-95).
 - Dev **`combat-targets-fixture`** resets runtime rows alongside HP + threat.
-- **22** NEO-93-focused tests green (`NpcRuntimeOperationsTests`, `InMemoryNpcRuntimeStateStoreTests`, fixture extension).
+- **23** NEO-93-focused tests green (`NpcRuntimeOperationsTests`, `InMemoryNpcRuntimeStateStoreTests`, fixture extension).
 
 ## Technical approach
 

server/NeonSprawl.Server.Tests/Game/Npc/NpcRuntimeOperationsTests.cs

@@ -239,5 +239,23 @@ public sealed class NpcRuntimeOperationsTests
         runtime.TryGet(PrototypeNpcRegistry.PrototypeNpcMeleeId, out var snapshot);
         Assert.Equal(NpcBehaviorState.Recover, snapshot.BehaviorState);
         Assert.Equal(T0.AddSeconds(4.5), snapshot.PhaseStartedUtc);
+        Assert.Equal(T0.AddSeconds(5), runtime.LastAdvancedUtc);
+    }
+
+    [Fact]
+    public void AdvanceAll_ShouldPreserveGradualCatchUp_AfterLongGapWithDeltaCap()
+    {
+        // Arrange
+        var (runtime, threat, behavior) = CreateFixture();
+        SetHolder(threat, PrototypeNpcRegistry.PrototypeNpcMeleeId);
+        Advance(T0, runtime, threat, behavior);
+        Advance(T0.AddSeconds(100), runtime, threat, behavior, maxDeltaSeconds: 5);
+        // Act
+        Advance(T0.AddSeconds(100.5), runtime, threat, behavior, maxDeltaSeconds: 5);
+        // Assert
+        Assert.Equal(T0.AddSeconds(10), runtime.LastAdvancedUtc);
+        runtime.TryGet(PrototypeNpcRegistry.PrototypeNpcMeleeId, out var snapshot);
+        Assert.Equal(NpcBehaviorState.Recover, snapshot.BehaviorState);
+        Assert.Equal(T0.AddSeconds(9), snapshot.PhaseStartedUtc);
     }
 }

server/NeonSprawl.Server/Game/Npc/NpcRuntimeOperations.cs

@@ -72,7 +72,7 @@ public static class NpcRuntimeOperations
                 behaviorRegistry);
         }
 
-        runtimeStore.LastAdvancedUtc = nowUtc;
+        runtimeStore.LastAdvancedUtc = windowEnd;
     }
 
     /// <summary>Resets all prototype NPC runtime rows to idle (dev fixture).</summary>