Add post changelogs

This replaces the manual `updated_date` field with a changelog flow
field so post updates can be recorded as dated entries.

The blog template now derives the "Last updated" metadata from the
latest changelog entry and renders the full changelog in the article
footer, with dedicated styling for compact change notes.

1 files changed, 1 insertions, 0 deletions

diff --git a/templates/blocks/changelog.html b/templates/blocks/changelog.html
new file mode 100644
index 0000000..eee2bf1
--- /dev/null
+++ b/templates/blocks/changelog.html
@@ -0,0 +1 @@
+{# Changelog entries are rendered by the blog post template. #}