kernel+ef: resolve readings, chain steps 1 and 2

Liturgical_day.citations has read "always empty until Plan 4" since Plan 3;
it is now filled. Rite.t gains a readings function, rite-supplied for the
same reason transfer_target is: what a day with no proper falls back to is a
rubric, not a universal. Calendar calls it and passes its own temporal
function as the callback the rite needs to reach another date.

Steps 1 and 2 only: the observed celebration's own proper, else the day's own
temporal slug. Nothing encodes "Lent has daily propers" -- the presence of an
entry is the discriminator.

1 files changed, 5 insertions, 1 deletions

diff --git a/test/test_calendar.ml b/test/test_calendar.ml
index 22f5f04..2f6df6d 100644
--- a/test/test_calendar.ml
+++ b/test/test_calendar.ml
@@ -99,9 +99,13 @@ module Fixture = struct
     let rec search d = if (occupant d).Cel.rank = Lo then d else search (D.add_days d 1) in
     search (D.add_days origin 1)
 
+  (* No fixture here exercises citations -- readings is a harmless constant
+     [], the same role [empty_layer] plays for the sanctoral side. *)
+  let readings ~observed:_ ~temporal:_ ~date:_ ~temporal_at:_ = []
+
   let rite : (season, rank) Rite.t =
     { Rite.id = "synthetic-calendar"; vocab; year_start; temporal; anchors = (fun _ -> []);
-      rules; season_runs = [ A; B ]; transfer_target }
+      rules; season_runs = [ A; B ]; transfer_target; readings }
 
   let entry ~month ~day ~slug ~rank =
     { Layer.date = (match Date_spec.fixed ~month ~day with Ok d -> d | Error e -> failwith e);