Add CODEOWNERS file

Author: dev-sujan

.github/CODEOWNERS

@@ -0,0 +1,32 @@
+# CODEOWNERS file for go-stl
+#
+# This file defines who is responsible for reviewing and approving changes
+# to different parts of the codebase.
+#
+# For more information, see:
+# https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners
+
+# Default owner for everything in the repo
+* @dev-sujan
+
+# Core library implementation
+/stl/ @dev-sujan
+
+# Documentation
+/docs/ @dev-sujan
+
+# Examples
+/examples/ @dev-sujan
+
+# Internal implementations
+/internal/ @dev-sujan
+
+# CI/CD workflows
+/.github/workflows/ @dev-sujan
+
+# Go module files
+go.mod @dev-sujan
+go.sum @dev-sujan
+
+# Configuration files
+/.golangci.yml @dev-sujan