Add BinaryTreeSort algorithm

- Implements Binary Tree Sort using BST with inorder traversal
- O(n log n) average case, O(n²) worst case time complexity
- Includes comprehensive test suite extending SortingAlgorithmTest

Author: PauLopNun

src/main/java/com/thealgorithms/sorts/BinaryTreeSort.java

@@ -0,0 +1,67 @@
+package com.thealgorithms.sorts;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Binary Tree Sort Algorithm Implementation
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Tree_sort">Binary Tree Sort Algorithm</a>
+ */
+public class BinaryTreeSort implements SortAlgorithm {
+
+    private static class TreeNode<T extends Comparable<T>> {
+        T data;
+        TreeNode<T> left;
+        TreeNode<T> right;
+
+        TreeNode(T data) {
+            this.data = data;
+            this.left = null;
+            this.right = null;
+        }
+    }
+
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        if (array == null || array.length <= 1) {
+            return array;
+        }
+        
+        TreeNode<T> root = null;
+        for (T value : array) {
+            root = insert(root, value);
+        }
+
+        List<T> result = new ArrayList<>();
+        inorder(root, result);
+        
+        for (int i = 0; i < array.length; i++) {
+            array[i] = result.get(i);
+        }
+        
+        return array;
+    }
+
+    private <T extends Comparable<T>> TreeNode<T> insert(TreeNode<T> root, T data) {
+        if (root == null) {
+            return new TreeNode<>(data);
+        }
+
+        if (SortUtils.less(data, root.data)) {
+            root.left = insert(root.left, data);
+        } else {
+            root.right = insert(root.right, data);
+        }
+
+        return root;
+    }
+
+    private <T extends Comparable<T>> void inorder(TreeNode<T> root, List<T> result) {
+        if (root != null) {
+            inorder(root.left, result);
+            result.add(root.data);
+            inorder(root.right, result);
+        }
+    }
+}

src/test/java/com/thealgorithms/sorts/BinaryTreeSortTest.java

@@ -0,0 +1,8 @@
+package com.thealgorithms.sorts;
+
+public class BinaryTreeSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new BinaryTreeSort();
+    }
+}