feat(combat): Phase L.1c wire live attack input

src/AcDream.Core/Combat/CombatModel.cs

@@ -27,6 +27,51 @@ public enum AttackHeight
     Low    = 3,
 }
 
+public enum CombatAttackAction
+{
+    Low,
+    Medium,
+    High,
+}
+
+/// <summary>
+/// Retail input-facing combat decisions. The heavyweight parts of the combat
+/// system remain server authoritative; this helper only maps UI intent to the
+/// mode / attack-height values sent on the wire.
+///
+/// References:
+/// named-retail ClientCombatSystem::ToggleCombatMode (0x0056C8C0),
+/// ClientCombatSystem::SetCombatMode (0x0056BE30), and
+/// ClientCombatSystem::ExecuteAttack (0x0056BB70).
+/// Cross-check: holtburger DesiredAttackProfile::to_attack_request only emits
+/// targeted attacks for Melee and Missile modes.
+/// </summary>
+public static class CombatInputPlanner
+{
+    public static CombatMode ToggleMode(
+        CombatMode currentMode,
+        CombatMode defaultCombatMode = CombatMode.Melee)
+    {
+        if ((currentMode & CombatMode.CombatCombat) != 0)
+            return CombatMode.NonCombat;
+
+        return (defaultCombatMode & CombatMode.CombatCombat) != 0
+            ? defaultCombatMode
+            : CombatMode.Melee;
+    }
+
+    public static bool SupportsTargetedAttack(CombatMode mode) =>
+        mode == CombatMode.Melee || mode == CombatMode.Missile;
+
+    public static AttackHeight HeightFor(CombatAttackAction action) => action switch
+    {
+        CombatAttackAction.Low => AttackHeight.Low,
+        CombatAttackAction.Medium => AttackHeight.Medium,
+        CombatAttackAction.High => AttackHeight.High,
+        _ => AttackHeight.Medium,
+    };
+}
+
 /// <summary>
 /// Retail uses a 15-bit flags enum for attack types — weapon categories.
 /// See r02 §2 + <c>ACE.Entity.Enum.AttackType</c>.