refactor(runtime): compose canonical game runtime root

src/AcDream.Runtime/Session/LiveSessionController.cs

@@ -15,6 +15,30 @@ public enum LiveSessionStartStatus
     Failed,
 }
 
+public readonly record struct LiveSessionOwnershipSnapshot(
+    bool IsDisposed,
+    bool IsDisposeRequested,
+    bool IsInWorld,
+    bool HasActiveSession,
+    bool HasRetiredSession,
+    bool HasPendingInitialReset,
+    bool HasPendingOperation,
+    int OperationDepth,
+    ulong Generation,
+    RuntimeTeardownStage LastTeardownStages)
+{
+    public bool IsConverged =>
+        IsDisposed
+        && IsDisposeRequested
+        && !IsInWorld
+        && !HasActiveSession
+        && !HasRetiredSession
+        && !HasPendingInitialReset
+        && !HasPendingOperation
+        && OperationDepth == 0
+        && LastTeardownStages == RuntimeTeardownStage.Complete;
+}
+
 public sealed record LiveSessionCharacterSelection(
     int ActiveIndex,
     uint CharacterId,
@@ -272,6 +296,24 @@ public sealed class LiveSessionController
         get { lock (_gate) return _disposed; }
     }
 
+    public LiveSessionOwnershipSnapshot CaptureOwnership()
+    {
+        lock (_gate)
+        {
+            return new LiveSessionOwnershipSnapshot(
+                _disposed,
+                _disposeRequested,
+                _inWorld,
+                _scope is not null,
+                _retiredScope is not null,
+                _pendingInitialResetHost is not null,
+                _pendingOperation is not null,
+                _operationDepth,
+                _generation,
+                _lastTeardownStages);
+        }
+    }
+
     public LiveSessionStartResult Start(
         LiveSessionConnectOptions options,
         ILiveSessionLifecycleHost host)