refactor(app): compose session and player startup

Move streaming, live-session, hydration, local-player, combat, and teleport construction behind the typed Phase-7 boundary. Add exact-owner runtime bindings and focused spawn-claim classification so partial startup rolls back without retaining old session targets while preserving the accepted construction and frame dependencies.

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

tests/AcDream.App.Tests/Streaming/LocalPlayerTeleportControllerTests.cs

@@ -13,6 +13,25 @@ namespace AcDream.App.Tests.Streaming;
 
 public sealed class LocalPlayerTeleportControllerTests
 {
+    [Fact]
+    public void DeferredNetworkOwnedBindingReleasesExactlyAndAllowsRebind()
+    {
+        var deferred = new DeferredLocalPlayerTeleportNetworkSink();
+        var first = new FakeNetworkSink();
+        var second = new FakeNetworkSink();
+
+        IDisposable firstBinding = deferred.BindOwned(first);
+        Assert.Throws<InvalidOperationException>(() => deferred.BindOwned(second));
+
+        firstBinding.Dispose();
+        using IDisposable secondBinding = deferred.BindOwned(second);
+        firstBinding.Dispose();
+        deferred.OnTeleportStarted(9);
+
+        Assert.Empty(first.Starts);
+        Assert.Equal([9u], second.Starts);
+    }
+
     [Fact]
     public void DestinationBeforeStart_IsReplayedOnceAfterPresentationActivates()
     {
@@ -684,6 +703,20 @@ public sealed class LocalPlayerTeleportControllerTests
         }
     }
 
+    private sealed class FakeNetworkSink : ILocalPlayerTeleportNetworkSink
+    {
+        public List<uint> Starts { get; } = [];
+        public void OnTeleportStarted(uint sequence) => Starts.Add(sequence);
+        public void OfferDestination(
+            WorldSession.EntityPositionUpdate update,
+            bool teleportTimestampAdvanced)
+        {
+        }
+        public void ResetSession()
+        {
+        }
+    }
+
     private sealed class FakePresentation : ILocalPlayerTeleportPresentation
     {
         private readonly List<string> _order;