Storylines: the same site told several ways, one per visitor, counted

Any text a person reads may be a list, one entry per storyline, every
list the same length. A visitor is given one storyline for the whole
site and reads it on every page and in every mail about their case.
Records and events carry the storyline; GET /report gives counts per
bucket, storyline and state, and nothing else.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GT37Z1Xtfd9pUuQtMTg6Yt

src/server/mod.rs

@@ -1,6 +1,7 @@
 #![cfg(feature = "ssr")]
 
 pub mod oidc;
+pub mod storyline;
 
 use arc_swap::ArcSwap;
 use axum::extract::FromRef;
@@ -21,18 +22,18 @@ pub struct AppState {
     /// message (see `content::watch_for_reload`) - readers never hold
     /// a lock, just an atomic pointer load, so a reload never blocks or
     /// is blocked by an in-flight request.
-    pub questions: Arc<ArcSwap<HashMap<String, Question>>>,
+    pub questions: Arc<ArcSwap<crate::content::Storylines<HashMap<String, Question>>>>,
     /// Every bucket's event-sourced state graph, loaded from
     /// `aggregates.yaml` (see `content::load_aggregates_from_gitea`) and
     /// hot-swapped alongside `questions` on the same reload. A bucket
     /// with no entry here isn't event-sourced - plain KV mutate-in-place
     /// still works (see `answers.rs`).
-    pub aggregates: Arc<ArcSwap<HashMap<String, crate::aggregates::AggregateSchema>>>,
+    pub aggregates: Arc<ArcSwap<crate::content::Storylines<HashMap<String, crate::aggregates::AggregateSchema>>>>,
     /// Site branding from the content repo's optional `site.yaml`
     /// (title, wordmark, hero kind) - hot-swapped with `questions`/
     /// `aggregates` on the same reload. Default = the historical uhhm
     /// look.
-    pub site: Arc<ArcSwap<crate::content::SiteConfig>>,
+    pub site: Arc<ArcSwap<crate::content::Storylines<crate::content::SiteConfig>>>,
     /// The access policy compiled from the content above (see
     /// `access.rs`), swapped with it on every reload. Every server entry
     /// point decides through this and nothing else.