refactor(runtime): own combat and magic intent

Move attack build/repeat state, combat-mode policy, authoritative auto-target transitions, and spell-cast intent beneath RuntimeActionState. Keep App as the input, world-query, DAT-policy, transport, and presentation adapter while preserving retail request and busy ordering. Add direct/graphical parity, reset, failure, and instance-isolation coverage.

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

src/AcDream.App/Combat/RuntimeCombatTargetOperationsSlot.cs

@@ -0,0 +1,63 @@
+using AcDream.Runtime.Gameplay;
+
+namespace AcDream.App.Combat;
+
+/// <summary>
+/// Early Runtime construction seam for the App-owned closest-hostile query.
+/// The slot owns no target identity or selection state.
+/// </summary>
+internal sealed class RuntimeCombatTargetOperationsSlot
+    : IRuntimeCombatTargetOperations
+{
+    private IRuntimeCombatTargetOperations? _owner;
+
+    public IDisposable BindOwned(IRuntimeCombatTargetOperations owner)
+    {
+        ArgumentNullException.ThrowIfNull(owner);
+        if (_owner is not null)
+            throw new InvalidOperationException(
+                "Runtime combat-target operations are already bound.");
+        _owner = owner;
+        return new Binding(this, owner);
+    }
+
+    private void Unbind(IRuntimeCombatTargetOperations expected)
+    {
+        if (ReferenceEquals(_owner, expected))
+            _owner = null;
+    }
+
+    public bool AutoTarget => _owner?.AutoTarget == true;
+    public uint? SelectClosestTarget() => _owner?.SelectClosestTarget();
+
+    private sealed class Binding : IDisposable
+    {
+        private RuntimeCombatTargetOperationsSlot? _slot;
+        private readonly IRuntimeCombatTargetOperations _expected;
+
+        public Binding(
+            RuntimeCombatTargetOperationsSlot slot,
+            IRuntimeCombatTargetOperations expected)
+        {
+            _slot = slot;
+            _expected = expected;
+        }
+
+        public void Dispose() =>
+            Interlocked.Exchange(ref _slot, null)?.Unbind(_expected);
+    }
+}
+
+internal sealed class LiveCombatTargetOperations(
+    Func<bool> autoTarget,
+    Func<uint?> selectClosestTarget)
+    : IRuntimeCombatTargetOperations
+{
+    private readonly Func<bool> _autoTarget = autoTarget
+        ?? throw new ArgumentNullException(nameof(autoTarget));
+    private readonly Func<uint?> _selectClosestTarget = selectClosestTarget
+        ?? throw new ArgumentNullException(nameof(selectClosestTarget));
+
+    public bool AutoTarget => _autoTarget();
+    public uint? SelectClosestTarget() => _selectClosestTarget();
+}