merge: celebrant Mass rubrics, and four rubrical corrections

colitur now prints what a real ordo prints for the Mass: which formulary is
said and how it was reached, the Gloria, the Creed, the preface, and the
commemorations with their Low-Mass/sung distinction. colitur rubrics joins
day and readings.

Four defects were found and fixed on the way, each by an external witness
rather than by inspection: the Creed said at Requiem Masses (RG 476(f)),
the missing bissextile shift of St Matthias and St Gabriel (2 041 leap
years), Rogation Monday and Tuesday coloured violet in Paschaltide (RG
119(b)), and the ferias after the Ascension resuming the wrong Sunday's
Mass rather than the Ascension's.

Validation gained a sixth layer and then some: the preface is checked
against three independent publishers over seven witness-years (FIUV, three
LMS editions, three extraordinaryform.org editions), none of which shares
the Divinum Officium -> missalemeum -> lectio lineage the older layers all
descend from.

1 files changed, 50 insertions, 0 deletions

diff --git a/test/test_differential.ml b/test/test_differential.ml
index 8c1dd8d..222328b 100644
--- a/test/test_differential.ml
+++ b/test/test_differential.ml
@@ -550,6 +550,17 @@ let jan_6_13_slug slug =
 let nativity_octave_day_slugs =
   [ "ef-nativity-octave-day-5"; "ef-nativity-octave-day-6"; "ef-nativity-octave-day-7" ]
 
+(* C41 (celebrant-rubrics-phase1, Bug 2, 2026-08-22): the six ferias
+   between the Ascension and the Friday before the Vigil of Pentecost that
+   repeat the Ascension's own Mass (data/ef/lectionary.sexp's own
+   [ascension_week_entries], bootstrap_lectionary.ml). The window's two
+   Saturdays are excluded here too, for the identical reason they carry no
+   lectionary entry: RG 78's votive Office of Our Lady wins first. *)
+let ascension_week_slugs =
+  [ "ef-easter-6-friday"; "ef-easter-7-monday"; "ef-easter-7-tuesday"; "ef-easter-7-wednesday";
+    "ef-easter-7-thursday"; "ef-easter-7-friday"
+  ]
+
 (* C18 (ef-sanctoral-audit, 2026-08-14): the closed set of colitur
    [status = Feast] sanctoral slugs whose bootstrapped [colour] was
    corrected against RG 124 (data/ef/adjustments.sexp's own audit-block
@@ -1096,6 +1107,36 @@ let rg33_vigil_slugs =
   [ "vigil-of-st-lawrence"; "vigil-of-the-nativity-of-st-john-the-baptist";
     "vigil-of-sts-peter-paul" ]
 
+(* C40 -- the calendarium's own bissextile (leap-year) footnote (February,
+   docs/research/LT.txt:5011-5014; see rite_ef/temporal_ef.ml's
+   [bissextile_fixed_key] for the full citation and mechanism), implemented
+   2026-08-22. lectio builds no such shift at all (confirmed directly
+   against the fixture: Matthias sits at 24 February and Gabriel of Our Lady
+   of Sorrows at 27 February in EVERY leap year the 2005-2050 fixture
+   covers, 11 of them), so every leap year now diverges on the two shifted
+   civil days: colitur vacates 24/27 February (Matthias/Gabriel move away)
+   and occupies 25/28 February instead, while lectio keeps the pre-shift
+   assignment on both.
+
+   Four shapes, one mechanism -- OLD position vacated (colitur no longer
+   matches lectio's still-there Matthias/Gabriel) and NEW position occupied
+   (colitur now shows a saint lectio's own unmoved date does not) -- each
+   checked by NAME on both sides, the same identity discipline C39 and
+   C6/C14 already apply, not merely a diff-set shape: a coincidental
+   same-shape diff on an unrelated 24/25/27/28 February slug would not match
+   any of the four literal-slug conjuncts below. *)
+let is_bissextile_shift_row (l : row) (c : row) ~month ~day =
+  month = 2
+  && Date.is_leap (year_of_date c.date)
+  && ((day = 24 && String.equal l.slug "matthias" && not (String.equal c.slug "matthias"))
+     || (day = 25 && String.equal c.slug "matthias" && not (String.equal l.slug "matthias"))
+     || (day = 27
+        && String.equal l.slug "gabriel-of-our-lady-of-sorrows"
+        && not (String.equal c.slug "gabriel-of-our-lady-of-sorrows"))
+     || (day = 28
+        && String.equal c.slug "gabriel-of-our-lady-of-sorrows"
+        && not (String.equal l.slug "gabriel-of-our-lady-of-sorrows")))
+
 let layer_c_reason (l : row) (c : row) diffs =
   let m = month_of_date l.date and d = day_of_date l.date in
   if diffs = [] then None
@@ -1158,6 +1199,15 @@ let layer_c_reason (l : row) (c : row) diffs =
     && (not (List.mem c.slug rg33_vigil_slugs))
     && subset diffs [ Slug_f; Rank; Colour_f; First_f; Gospel_f ]
   then Some "C39"
+  else if is_bissextile_shift_row l c ~month:m ~day:d && subset diffs [ Slug_f; Rank; Colour_f; First_f; Gospel_f ]
+  then Some "C40"
+  (* C41 -- the Ascension-repeat rubric (see [ascension_week_slugs]'s own
+     citation above). SAME slug both sides ([Slug_f] never diffs here: the
+     six slugs already exist in lectio's own EF walkback, only their
+     resolved TEXT differs), rank/season/colour agree (both an ordinary
+     Class4 Paschaltide feria), and only the citation itself changes. *)
+  else if List.mem c.slug ascension_week_slugs && subset diffs [ First_f; Gospel_f ]
+  then Some "C41"
   (* C25 -- CLOSED, BVM Saturday Mass (2026-08-17), predicate removed: 0 rows.
      Its days are unoccupied IV-class Saturdays, so they carry RG 78's office
      and now RG 309(a)'s Mass for it, which answers before step 3's walkback