Did some code cleanup,

added some extra thingies.
switched to spans. Let google gemini do whatever it wanted..

TestProject1/FuzzTest.cs

@@ -21,7 +21,7 @@ public class BTreeFuzzTests
         // CONFIGURATION
         const int Iterations = 100_000; // High enough to trigger all splits/merges
         const int KeyRange = 5000;      // Small enough to cause frequent collisions
-        const bool showOps = true;
+        const bool showOps = false;
         int Seed = 2135974; // Environment.TickCount;
         
         // ORACLES
@@ -167,4 +167,4 @@ public class BTreeFuzzTests
             throw new Exception("Enumerator has extra items!");
         }
     }
-}
+}