Web dashboard v2 step 1: public summaries, legacy issue fallback

Public issue pages and the Atom feed now carry each pick's summary and
'Why it's here' line (bodies, The Brief, World Briefing and comments stay
private). Issues stored before issues.issue_json existed rebuild their
colophon and Behind the paper from issues.report_json / the run row and
candidate_runs, and recover the World Briefing chapter from the EPUB on
disk. The dev seed mirrors that legacy shape.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NHyYupFdBiR4VfoUM7NjSM

README.md

@@ -189,8 +189,9 @@ the database or takes the lock, so it is safe to run next to a live `generate`.
 ## Web site and dashboard
 
 The server is both the public newspaper index and the private operator UI. An
-anonymous visitor sees only titles, authors, sources, metadata and outbound
-comment links; generated and scraped text stays private. A signed-in `user`
+anonymous visitor sees titles, authors, sources, metadata, AI summaries, why
+lines and outbound comment links; article bodies, the Brief, the World Briefing
+and comments stay private. A signed-in `user`
 sees complete issues and article chapters and can download artifacts. An
 `admin` can additionally rate articles and use every `/dashboard/*` page,
 including settings and jobs. Personalization is shared across accounts for now.