chore: add documentation PR checklist (TreemapVisualization) [no_release]

Author: lachiebol

pull_request_template.md

@@ -26,3 +26,4 @@
 - [✔/✖/NA] Version bumped?
 - [✔/✖/NA] I have understood, reviewed, and tested all AI outputs before use
 - [✔/✖/NA] All AI instructions respect security, IP, and privacy rules
+- [✔/✖/NA] Documentation updated?