refactor(runtime): own magic and player state

Move the coupled Spellbook and LocalPlayerState into one Runtime-owned character graph, route content, live-session, retained UI, reset, and shutdown through that exact owner, and delete the duplicate desired-component snapshot from inventory state. Preserve synchronous retail update and reset ordering while adding independent-instance and retryable-failure coverage.

Co-authored-by: Codex <codex@openai.com>

tests/AcDream.App.Tests/Runtime/RuntimeInventoryOwnershipTests.cs

@@ -27,6 +27,10 @@ public sealed class RuntimeInventoryOwnershipTests
             "new AcDream.Core.Items.ExternalContainerState",
             source,
             StringComparison.Ordinal);
+        Assert.DoesNotContain(
+            "DesiredComponentState",
+            source,
+            StringComparison.Ordinal);
     }
 
     [Fact]
@@ -50,8 +54,8 @@ public sealed class RuntimeInventoryOwnershipTests
             "_domain.Inventory.Transactions.CompleteUse(error)",
             session,
             StringComparison.Ordinal);
-        Assert.Contains(
-            "OnDesiredComponents: _domain.Inventory.DesiredComponents.Replace",
+        Assert.DoesNotContain(
+            "_domain.Inventory.DesiredComponents",
             session,
             StringComparison.Ordinal);
         AssertAppearsInOrder(