Initial import of IC.Rebuild

Core/RangePolicies.cs

@@ -0,0 +1,32 @@
+namespace ICRebuild.Core;
+
+public readonly struct ActionRangeCheckScope : IDisposable
+{
+    [ThreadStatic] private static bool active;
+    private readonly bool previous;
+    private ActionRangeCheckScope(bool allowed) { previous=active; active=allowed; }
+    public static ActionRangeCheckScope Enter(bool allowed) => new(allowed);
+    public static bool Active => active;
+    public void Dispose() => active=previous;
+}
+
+public static class TargetRadiusPolicy
+{
+    // One target radius is used consistently by native drawing, attack checks and gap-closer placement.
+    // Never add the bonus to the player's own radius (which would double the landing displacement).
+    public static float Adjust(GameFrame frame,nint actor,uint entityId,float original,float extra) =>
+        frame.Ready && actor!=0 && actor!=frame.LocalAddress && actor==frame.TargetAddress && entityId==frame.TargetEntityId && float.IsFinite(original) && original>=0
+            ? original+Policies.FiniteClamp(extra,0,5) : original;
+}
+
+public sealed record TargetRadiusObservation(uint EntityId,float Original,float Effective);
+
+public readonly struct NativeTargetRingScope : IDisposable
+{
+    [ThreadStatic] private static bool active;
+    private readonly bool previous;
+    private NativeTargetRingScope(bool allowed) { previous=active; active=allowed; }
+    public static NativeTargetRingScope Enter(bool allowed) => new(allowed);
+    public static bool Active => active;
+    public void Dispose() => active=previous;
+}