Fix .NET Standard compatibility:

- Replace double.DegreesToRadians/RadiansToDegrees with Math-based conversions
- Replace Random.Shared with thread-local Random for thread safety

src/StandardLibrary/Functions/Angle/Degrees.cs

@@ -26,8 +26,8 @@
                 var input = _args[0].Value;
                 decimal value = Convert.ToDecimal(input.Value);
 
-                // Convert radians to degrees
+                // Convert radians to degrees (compatible with .NET Standard)
-                return new FunctionValue(FunctionValueType.Numeric, double.RadiansToDegrees((double)value));
+                return new FunctionValue(FunctionValueType.Numeric, (double)value * (180.0 / Math.PI));
             });
         }
     }

src/StandardLibrary/Functions/Angle/Radians.cs

@@ -26,8 +26,8 @@
                 var input = _args[0].Value;
                 decimal value = Convert.ToDecimal(input.Value);
 
-                // Convert degrees to radians
+                // Convert degrees to radians (compatible with .NET Standard)
-                return new FunctionValue(FunctionValueType.Numeric, double.DegreesToRadians((double)value));
+                return new FunctionValue(FunctionValueType.Numeric, (double)value * (Math.PI / 180.0));
             });
         }
     }

src/StandardLibrary/Functions/Random/RandomBase.cs

@@ -8,13 +8,11 @@ namespace CSMic.StandardLibrary.Functions.Random
 {
     public abstract class RandomBase : FunctionBase
     {
-        protected static System.Random RandomNumberGenerator
+        // Provide a thread-local random to approximate Random.Shared in .NET Standard
-        {
+        private static readonly System.Threading.ThreadLocal<System.Random> s_threadLocalRandom =
-            get
+            new System.Threading.ThreadLocal<System.Random>(() => new System.Random());
-            {
+
-                return System.Random.Shared;
+        protected static System.Random RandomNumberGenerator => s_threadLocalRandom.Value!;
-            }
-        }
 
         protected static decimal NextDecimal()
         {