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/lib/kernel/preface.mli b/lib/kernel/preface.mli
new file mode 100644
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+(** The Mass preface (Missale Romanum, Rubricae Generales, Caput XVII("De
+    Ritibus servandis in celebratione Missae"), "H) De praefatione", RG
+    482-499; docs/research/LT.txt, grep "praefatione dicitur quae cuique").
+
+    RG 482 gives the resolution chain in full: {i "Praefatio dicitur quae
+    cuique Missae propria est; qua deficiente, dicitur praefatio de
+    Tempore, secus communis"} -- the Mass's own PROPER preface; failing
+    that, the SEASONAL ("de Tempore") one; failing that, the COMMON. RG
+    483: {i "Nulla commemoratio, in Missa occurrens, praefationem propriam
+    inducit"} -- a commemoration never induces its own proper preface,
+    which is why {!Rite_ef.Rubrics_ef.preface} (the one rite that
+    implements this so far) reads only the day's OBSERVED celebration,
+    never its commemorations, the identical discipline {!Rite.t.creed}'s
+    own RG 476(e) already established.
+
+    RG 484-497 enumerate the fourteen named propers -- Nativity, Epiphany,
+    Lent, Holy Cross, [the Chrism Mass, out of scope: see the .ml's own
+    N/A note], Easter, Ascension, the Sacred Heart, Christ the King, the
+    Holy Spirit, the Trinity, the Blessed Virgin Mary, St Joseph, the
+    Apostles. RG 498 is the residual Common; RG 499 the Requiem.
+
+    A KERNEL type, not a rite-specific one (the same placement as
+    {!Colour}, {!Subject}, {!Mass_formulary}): {!Liturgical_day.t} is
+    parameterised only over a rite's season/rank, so any field it carries
+    generically must live here, even though only the EF rite constructs a
+    value of it today -- CLAUDE.md's own "generalise when forced, not
+    speculatively" stance, already the precedent {!Mass_formulary}
+    follows. *)
+
+type t =
+  | Nativity  (** RG 484 *)
+  | Epiphany  (** RG 485 *)
+  | Lent  (** RG 486, "de Quadragesima" *)
+  | Holy_cross  (** RG 487, "de sancta Cruce" *)
+  | Easter  (** RG 489, "paschalis" *)
+  | Ascension  (** RG 490 *)
+  | Sacred_heart  (** RG 491, "de Ss.mo Corde Iesu" *)
+  | Christ_the_king  (** RG 492, "de D. N. Iesu Christo Rege" *)
+  | Holy_spirit  (** RG 493, "de Spiritu Sancto" *)
+  | Trinity  (** RG 494, "de Ss.ma Trinitate" *)
+  | Bvm  (** RG 495, "de beata Maria Virgine" *)
+  | St_joseph  (** RG 496, "de S. Ioseph" *)
+  | Apostles  (** RG 497, "de Apostolis" *)
+  | Common  (** RG 498, "communis" -- the residual when nothing else applies *)
+  | Requiem  (** RG 499, "defunctorum" *)
+[@@deriving sexp]
+
+val all : t list
+val to_string : t -> string
+val of_string : string -> t option