port(m1): wave 7j — Material/Plane/Socket overloads + IDictionary extension (24->12)

- Material.SetVector(int nameID, Vector4); Plane(Vector3, float d) ctor; Socket.On
  (SocketIOEventTypes, callback) overload.
- Global GetValueOrDefault(this IDictionary<,>) extension — the BCL form only binds to
  IReadOnlyDictionary, so the IDictionary call mis-resolved to JsonDataExtension.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

SVSim.BattleEngine/Shim/External/SdkStubs.cs

@@ -99,3 +99,13 @@ namespace BestHTTP.Decompression.Zlib
 public static class TimeNativePlugin { public static float GetDeviceOperatingTime() => 0f; }
 public static class Packsize { public static bool Test() => true; }
 public static class DllCheck { public static bool Test() => true; }
+
+// The BCL's CollectionExtensions.GetValueOrDefault only binds to IReadOnlyDictionary;
+// copied code calls it on an IDictionary<,> static type (where the only by-name match is
+// the copied JsonDataExtension.GetValueOrDefault(JsonData,...) — wrong receiver). Supply the
+// IDictionary form globally so the call resolves.
+public static class ShimDictionaryExtensions
+{
+    public static TValue GetValueOrDefault<TKey, TValue>(this System.Collections.Generic.IDictionary<TKey, TValue> dict, TKey key, TValue defaultValue)
+        => dict != null && dict.TryGetValue(key, out var v) ? v : defaultValue;
+}