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.Runtime/Gameplay/RuntimeCombatModeState.cs

@@ -0,0 +1,94 @@
+using AcDream.Core.Combat;
+using AcDream.Core.Items;
+
+namespace AcDream.Runtime.Gameplay;
+
+public enum RuntimeCombatModeRequestStatus
+{
+    Inactive,
+    Rejected,
+    Sent,
+}
+
+public readonly record struct RuntimeCombatModeRequestResult(
+    RuntimeCombatModeRequestStatus Status,
+    CombatMode Mode,
+    string? Notice = null);
+
+public interface IRuntimeCombatModeOperations
+{
+    bool IsInWorld { get; }
+    IReadOnlyList<ClientObject> GetOrderedEquipment();
+    void NotifyExplicitCombatModeRequest();
+    void SendChangeCombatMode(CombatMode mode);
+}
+
+/// <summary>
+/// Presentation-independent owner for retail's explicit combat-mode command.
+/// App supplies ordered equipment, transport, and the auto-wield cancellation
+/// edge; Runtime owns the exact default selection and local state transition.
+/// </summary>
+/// <remarks>
+/// Port of <c>ClientCombatSystem::GetDefaultCombatMode @ 0x0056B310</c>
+/// and <c>ClientCombatSystem::ToggleCombatMode @ 0x0056C8C0</c>.
+/// </remarks>
+public sealed class RuntimeCombatModeState
+{
+    private readonly CombatState _combat;
+    private readonly IRuntimeCombatModeOperations _operations;
+
+    public RuntimeCombatModeState(
+        CombatState combat,
+        IRuntimeCombatModeOperations operations)
+    {
+        _combat = combat ?? throw new ArgumentNullException(nameof(combat));
+        _operations = operations
+            ?? throw new ArgumentNullException(nameof(operations));
+    }
+
+    public RuntimeCombatModeRequestResult Toggle()
+    {
+        if (!_operations.IsInWorld)
+        {
+            return new RuntimeCombatModeRequestResult(
+                RuntimeCombatModeRequestStatus.Inactive,
+                _combat.CurrentMode);
+        }
+
+        // Every explicit user request supersedes auto-wield settlement,
+        // including a request GetDefaultCombatMode later rejects.
+        _operations.NotifyExplicitCombatModeRequest();
+
+        CombatMode currentMode = _combat.CurrentMode;
+        CombatMode nextMode;
+        if (currentMode != CombatMode.NonCombat)
+        {
+            nextMode = CombatMode.NonCombat;
+        }
+        else
+        {
+            DefaultCombatModeDecision decision =
+                CombatInputPlanner.GetDefaultCombatModeDecision(
+                    _operations.GetOrderedEquipment());
+            if (decision.IncompatibleHeldItem is { } held)
+            {
+                string notice =
+                    $"You can't enter combat mode while wielding the {held.GetAppropriateName()}";
+                return new RuntimeCombatModeRequestResult(
+                    RuntimeCombatModeRequestStatus.Rejected,
+                    currentMode,
+                    notice);
+            }
+
+            nextMode = CombatInputPlanner.ToggleMode(
+                currentMode,
+                decision.Mode);
+        }
+
+        _operations.SendChangeCombatMode(nextMode);
+        _combat.SetCombatMode(nextMode);
+        return new RuntimeCombatModeRequestResult(
+            RuntimeCombatModeRequestStatus.Sent,
+            nextMode);
+    }
+}