refactor: unify monitor abort lifecycle handling

changelog/fragments/README.md

@@ -0,0 +1,13 @@
+# Changelog Fragments
+
+Use this directory when a PR should not edit `CHANGELOG.md` directly.
+
+- One fragment file per PR.
+- File name recommendation: `pr-<number>.md`.
+- Include at least one line with both `#<pr>` and `thanks @<contributor>`.
+
+Example:
+
+```md
+- Fix LINE monitor lifecycle wait ownership (#27001) (thanks @alice)
+```