docs(changelog): Release version 0.1.3

Close the Unreleased section and create release entry for v0.1.3
dated 2025-11-25.

Author: ahojukka5

CHANGELOG.md

@@ -7,6 +7,8 @@ SPDX-License-Identifier: AGPL-3.0-or-later
 
 ## [Unreleased]
 
+## [0.1.3] - 2025-11-25
+
 ### Added
 
 - **Examples**: Custom coordinate system example in `examples/17_custom_coordinate_system.cpp`