Refresh Story Bible reference ranges when the header folds or unfolds

Folding/unfolding the header moves the frontmatter in or out of
`buffer`, shifting every char offset into it, but after_view_change()
never recomputed current_references — so the cached ranges stayed
pointing at pre-toggle positions and highlights landed on unrelated
words. Recompute them alongside the other view-state invalidations it
already does.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/workspace.rs

@@ -541,6 +541,11 @@ impl App {
         self.spell_menu = None;
         self.clear_lt();
         self.autocomplete = None;
+        // Story Bible reference ranges are char offsets into `buffer` too —
+        // stale ones (from before the header moved in or out) land on
+        // whatever text now happens to sit `header.len()` characters away
+        // from the real mention.
+        self.update_current_references();
     }
 
     /// How many header fields are hidden right now, for the toggle's label.