port(m1): wave 6c — Unity + Steam/FB/Adjust static-class shims (696->572)

Off-battle-path static surfaces (CS0103 cluster):
- UnityStatics: Gizmos, Physics2D, Caching, GUIUtility, Cursor, ColorUtility,
  ScreenCapture, RenderSettings, JsonUtility, Social + CursorLockMode enum.
- RaycastHit2D implicit-bool operator; ILocalUser in SocialPlatforms.
- Steamworks: Callback<T>.Create, AppId_t/CSteamID/HAuthTicket/SteamNetworkingIdentity,
  MicroTxn/GetAuthSessionTicket response structs, SteamAPI/User/Utils/Client statics.
  Removed empty dup GetAuthSessionTicketResponse_t from ThirdParty.cs.
- Facebook.Unity: FB + ILoginResult + FacebookDelegate<T>; com.adjust.sdk.Adjust;
  global TimeNativePlugin/Packsize native-plugin stubs.

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

SVSim.BattleEngine/Shim/UnityEngine/UnityShim.cs

@@ -46,7 +46,7 @@ namespace UnityEngine
     public struct Plane { public Plane(Vector3 normal, Vector3 point) { } public bool Raycast(Ray r, out float enter) { enter = 0; return false; } }
     public struct Ray { public Ray(Vector3 origin, Vector3 dir) { this.origin = origin; this.direction = dir; } public Vector3 origin; public Vector3 direction; public Vector3 GetPoint(float d) => origin; }
     public struct RaycastHit { public Vector3 point; public Vector3 normal; public float distance; public Collider collider; public Transform transform; public GameObject gameObject; }
-    public struct RaycastHit2D { public Vector3 point; public Vector3 normal; public float distance; public Collider2D collider; public Transform transform; }
+    public struct RaycastHit2D { public Vector3 point; public Vector3 normal; public float distance; public Collider2D collider; public Transform transform; public static implicit operator bool(RaycastHit2D hit) => hit.collider != null; }
     public struct LayerMask { public int value; public static int NameToLayer(string n) => 0; public static implicit operator int(LayerMask m) => m.value; }
 
     // ---- core object model ----