stabilizaiton work - projects rework for maintenanceability and ui livening

src/__Libraries/StellaOps.Provcache/DecisionDigestBuilder.Hashing.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Security.Cryptography;
+
+namespace StellaOps.Provcache;
+
+public sealed partial class DecisionDigestBuilder
+{
+    private static string ComputeHash(ReadOnlySpan<byte> data)
+    {
+        Span<byte> hash = stackalloc byte[32];
+        SHA256.HashData(data, hash);
+        return $"sha256:{Convert.ToHexStringLower(hash)}";
+    }
+
+    private static string StripPrefix(string hash)
+    {
+        if (hash.StartsWith("sha256:", StringComparison.OrdinalIgnoreCase))
+            return hash[7..];
+        return hash;
+    }
+}