Update Murmur3 to use cryptographically secure seed

Changed the Seed field from a constant to a runtime-generated value using a new GenerateSeed() method with RandomNumberGenerator. Added System.Security.Cryptography import for secure random seed generation, supporting both .NET 6.0+ and earlier versions.

Author: dmiller

Clojure/Clojure/Lib/Murmur3.cs

@@ -16,6 +16,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
+using System.Security.Cryptography;
 using System.Text;
 
 namespace clojure.lang
@@ -37,7 +38,7 @@ public static class Murmur3
     {
         #region Data
 
-        const int Seed = 0;
+        static readonly uint Seed = GenerateSeed();
         const uint C1 = 0xcc9e2d51;
         const uint C2 = 0x1b873593;
         const int R1 = 15;
@@ -220,6 +221,18 @@ private static uint RotateLeft(uint x, int n)
         {
             return (x << n) | (x >> (32 - n));
         }
+
+        private static uint GenerateSeed()
+        {
+#if NET6_0_OR_GREATER
+            return unchecked((uint)RandomNumberGenerator.GetInt32(int.MinValue, int.MaxValue));
+#else
+            byte[] bytes = new byte[4];
+            using (var rng = RandomNumberGenerator.Create())
+                rng.GetBytes(bytes);
+            return BitConverter.ToUInt32(bytes, 0);
+#endif
+        }
         #endregion
     }
 }