WIP: Add guide chapters SQL union to newsletter template

Adds blog_chapter query to the content CTE in the newsletter SQL.
Still needs: URL handling in collected CTE, JS rendering with
first-3-paragraph truncation and [... word count] suffix, chapter
state management, and extras count integration.

https://claude.ai/code/session_01Df7tNiUDSXVwvF1yeChynr

Author: claude

blog-to-newsletter.html

@@ -542,6 +542,26 @@ <h2>Links sent in previous newsletters</h2>
     '' as external_url
   from blog_note
   union all
+  select
+    c.id,
+    'chapter' as type,
+    c.title,
+    c.created,
+    c.slug,
+    'No HTML' as html,
+    json_object(
+      'created', date(c.created),
+      'title', c.title,
+      'body', c.body,
+      'chapter_slug', c.slug,
+      'guide_title', g.title,
+      'guide_slug', g.slug
+    ) as json,
+    'https://simonwillison.net/guides/' || g.slug || '/' || c.slug || '/' as external_url
+  from blog_chapter c
+  join blog_guide g on c.guide_id = g.id
+  where c.is_draft = 0
+  union all
   select
     rowid,
     'til' as type,