Did some code cleanup,

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

TestProject1/UnitTest1.cs

@@ -0,0 +1,70 @@
+namespace TestProject1;
+
+using Xunit;
+using PersistentMap;
+
+public class BasicTests
+{
+    private readonly UnicodeStrategy _strategy = new UnicodeStrategy();
+
+    [Fact]
+    public void Transient_InsertAndGet_Works()
+    {
+        var map = BaseOrderedMap<string, int, UnicodeStrategy>.CreateTransient(_strategy);
+
+        map.Set("Apple", 1);
+        map.Set("Banana", 2);
+        map.Set("Cherry", 3);
+
+        Assert.True(map.TryGetValue("Apple", out int v1));
+        Assert.Equal(1, v1);
+        
+        Assert.True(map.TryGetValue("Banana", out int v2));
+        Assert.Equal(2, v2);
+
+        Assert.False(map.TryGetValue("Date", out _));
+    }
+
+    [Fact]
+    public void Transient_Update_Works()
+    {
+        var map = BaseOrderedMap<string, int, UnicodeStrategy>.CreateTransient(_strategy);
+        map.Set("Key", 100);
+        map.Set("Key", 200); // Overwrite
+
+        map.TryGetValue("Key", out int val);
+        Assert.Equal(200, val);
+    }
+
+    [Fact]
+    public void Transient_Remove_Works()
+    {
+        var map = BaseOrderedMap<string, int, UnicodeStrategy>.CreateTransient(_strategy);
+        map.Set("A", 1);
+        map.Set("B", 2);
+        map.Set("C", 3);
+
+        map.Remove("B");
+
+        Assert.True(map.ContainsKey("A"));
+        Assert.False(map.ContainsKey("B"));
+        Assert.True(map.ContainsKey("C"));
+    }
+
+    [Fact]
+    public void Transient_PrefixCollision_HandlesCollision()
+    {
+        // UnicodeStrategy only packs the first 4 chars.
+        // "Test1" and "Test2" have the same prefix "Test".
+        var map = BaseOrderedMap<string, int, UnicodeStrategy>.CreateTransient(_strategy);
+
+        map.Set("Test1", 1);
+        map.Set("Test2", 2);
+
+        Assert.True(map.TryGetValue("Test1", out var v1));
+        Assert.Equal(1, v1);
+
+        Assert.True(map.TryGetValue("Test2", out var v2));
+        Assert.Equal(2, v2);
+    }
+}