The Vue and Pinia migration's entries move out of CHANGELOG.md into
changelog.d/0000-vue-and-pinia.md, newest first, as the contributing guide
asks. 0000 stands in for the pull request number until it is opened. The
migration plan's cleanup step now records where it stands: the template
expansion is gone, the pattern is required for new UI, the page-level
markup tests render the real views, the attribute translation pass waits
for vue-i18n, and a host panel registration API waits for its first host.