refactor(app): compose content effects and audio startup

Move Phase-2 startup behind typed composition/publication boundaries, replace the GameWindow-capturing PhysicsScript gate with a focused deferred source, and own animation-hook registrations reversibly. Make OpenAL construction and teardown transactional so every device, context, source, and buffer prefix is retryable without replay.

src/AcDream.App/Rendering/Vfx/EntityEffectAdvanceSource.cs

@@ -0,0 +1,63 @@
+namespace AcDream.App.Rendering.Vfx;
+
+internal interface IEntityEffectAdvanceSource
+{
+    bool CanAdvanceOwner(uint ownerLocalId);
+}
+
+/// <summary>
+/// Focused late-binding edge between the Phase-2 PhysicsScript runner and the
+/// Phase-6 live effect authority. Before live presentation exists, scripts are
+/// unconstrained exactly as the former null-safe callback was; after binding,
+/// the canonical effect owner decides whether its current pose can advance.
+/// </summary>
+internal sealed class DeferredEntityEffectAdvanceSource : IEntityEffectAdvanceSource
+{
+    private readonly object _gate = new();
+    private IEntityEffectAdvanceSource? _target;
+    private bool _deactivated;
+
+    public void Bind(IEntityEffectAdvanceSource target)
+    {
+        ArgumentNullException.ThrowIfNull(target);
+        lock (_gate)
+        {
+            ObjectDisposedException.ThrowIf(_deactivated, this);
+            if (_target is not null && !ReferenceEquals(_target, target))
+            {
+                throw new InvalidOperationException(
+                    "Entity-effect script advancement is already bound.");
+            }
+
+            _target = target;
+        }
+    }
+
+    public void Unbind(IEntityEffectAdvanceSource target)
+    {
+        ArgumentNullException.ThrowIfNull(target);
+        lock (_gate)
+        {
+            if (ReferenceEquals(_target, target))
+                _target = null;
+        }
+    }
+
+    public void Deactivate()
+    {
+        lock (_gate)
+        {
+            _deactivated = true;
+            _target = null;
+        }
+    }
+
+    public bool CanAdvanceOwner(uint ownerLocalId)
+    {
+        lock (_gate)
+        {
+            return _deactivated
+                || _target?.CanAdvanceOwner(ownerLocalId) != false;
+        }
+    }
+}

src/AcDream.App/Rendering/Vfx/EntityEffectController.cs

@@ -22,7 +22,8 @@ namespace AcDream.App.Rendering.Vfx;
 /// (<c>0x00513260</c>) and both <c>play_default_script</c> overloads
 /// (<c>0x005132B0</c>, <c>0x00513300</c>).
 /// </remarks>
-public sealed class EntityEffectController : IAnimationHookSink
+public sealed class EntityEffectController : IAnimationHookSink,
+    IEntityEffectAdvanceSource
 {
     private readonly LiveEntityRuntime _liveEntities;
     private readonly PhysicsScriptRunner _runner;