Merge branch 'ef-triduum-litanies': the Sacred Triduum's Latin identity

Gives Holy Thursday, Good Friday and Holy Saturday the names the Missal
prints for them, taken from each Office's own running header: 'Feria V
in Cena Domini', 'Feria VI in Passione et Morte Domini', 'Sabbato
sancto'. Rank and colour were already correct; only the identity was
missing, the same shape the Holy Family had. The slug is deliberately
unchanged -- it is the lectionary key -- and the names are Latin, which
avoids promoting an English value from the oracle the engine is checked
against.

Not 'Feria VI Parasceve': that phrase occurs zero times as a title in
either photographic scan, appearing only inside the Johannine Passion
text, and RG 132(a) writes 'feriae VI in Passione et Morte Domini'.

Output is byte-identical across all 8417 years -- colitur day prints no
name column -- but layer 5 does see it: describe gained name_la, and
reverting the change reddens six pins.

The Major Litanies (RG 80) and the Rogation Wednesday commemoration were
investigated to the same depth, scan-verified, cited, and deliberately
not built. Rogation Wednesday is genuinely blocked: Easter+38 coincides
with the Ascension Vigil, so no Fixed date-spec can anchor it. The Major
Litanies are tractable in the rite module -- the two blockers first
recorded for them were false, and are retracted here -- but 25 April is
St Mark, II class, so under RG 111(c) a privileged Litanies
commemoration would displace the day's existing ordinary commemoration
in ~97.7% of years. That blast radius is unmeasured, and measuring it is
the prerequisite for its own task.

1 files changed, 101 insertions, 1 deletions

diff --git a/lib/rites/rite_ef/temporal_ef.ml b/lib/rites/rite_ef/temporal_ef.ml
index bbd88ec..4b59ff4 100644
--- a/lib/rites/rite_ef/temporal_ef.ml
+++ b/lib/rites/rite_ef/temporal_ef.ml
@@ -154,6 +154,97 @@ let holy_name_fallback_date y = mk y 1 2
 let holy_name_names =
   Colitur_kernel.Names.of_list [ (Colitur_kernel.Lang.of_string_exn "la", "Sanctissimi Nominis Iesu") ]
 
+(* RG 91 entry 2 (Sacred Triduum) ranks Holy Thursday/Good Friday/Holy
+   Saturday above even entry 7's own I-class ferias (this file's own comment
+   on [privileged_feria]), but [temporal] constructs no proper NAMED office
+   for any of the three (ef-triduum-litanies task, Gap 1) -- they fall
+   through to the generic Passiontide ferial branch below like any other day
+   of Holy Week. The slug STAYS that generic key: RG 91 entry 2 is already
+   identified structurally, off the day's own Easter offset and rank
+   (Precedence_ef.band's own entry-2 branch), never off the slug, so
+   renaming it would touch precedence for no reason and would break the
+   lectio differential's own slug mapping for these three lectionary keys
+   (the same reasoning [holy_family_sunday]'s own citation above gives for
+   keeping "ef-time-after-epiphany-sunday-1"). What was actually missing is
+   IDENTITY alone, closed the same way RG 17(b)/(a) (Holy Family/Holy Name,
+   above) already were: Latin, not English, in [names] -- zero circularity
+   (an English name would mean reading missalemeum's own title text, the
+   oracle this exact axis is compared against, to decide colitur's own
+   "ground truth").
+
+   Both photographic scans, word for word, corroborated by the electronic
+   transcription's own table-of-contents-style listing at the identical
+   three headings (docs/research/rules-register.md; three-way agreement, no
+   scan-vs-transcription conflict to adjudicate here -- these three headings
+   sit OUTSIDE the Mass-propers body text the transcription is documented
+   elsewhere as missing almost all of, in a title/running-header line it
+   carries just the same): "FERIA QUINTA IN CENA DOMINI" / running header
+   "Feria V in Cena Domini" (Holy Thursday); "FERIA SEXTA / IN PASSIONE ET
+   MORTE DOMINI" (Good Friday -- NOT the informal "Feria VI Parasceve" the
+   transcription uses in passing elsewhere in an unrelated rubric; this is
+   the Missal's own Mass-propers section title, confirmed as the running
+   header on every page of that Office in both scans); "SABBATO SANCTO"
+   (Holy Saturday, both scans, with "I classis" printed directly beneath the
+   heading).
+
+   [subject = Lord] is also set (Holy Family/Holy Name needed it only
+   because Precedence_ef.band's entry 14 reads [subject] to outrank a
+   colliding fixed feast; entry 2 here needs no such thing --
+   Precedence_ef.band's own entry-2 branch tests only [rank] and the Easter
+   offset). Tagged anyway because it is simply true (the Last Supper, the
+   Passion and Death, the entombment are textbook mysteries of the Lord) and
+   safe: Precedence_ef.disposition's RG 112(a) branch (a mystery of the Lord
+   excluding a commemoration of ANOTHER mystery of the same Divine Person)
+   only fires when BOTH sides of an occurrence are tagged [Lord], and no
+   [Lord]-subject entry in data/ef/sanctoral.sexp has a fixed civil date
+   inside Holy Week's own movable range (earliest 19 March, latest 24 April;
+   the register's own subject audit lists exactly six [Lord]-tagged
+   entries, all fixed in January, February, JULY, August, September or
+   November -- the Precious Blood, 1 July, was omitted from this list until
+   the fix-round review counted six entries against five months)
+   -- and any [Class1] sanctoral entry that DOES land there (e.g. a
+   transferred Annunciation) reaches Precedence_ef.disposition's EARLIER,
+   subject-blind "I class, not a Sunday -> Transfer" branch first
+   regardless, so RG 112(a)'s branch is never reached for it either way.
+   Measured, not merely argued: this task's own full 1583-9999 blast-radius
+   sweep (git archive, pre- vs post-change) shows zero
+   [observed]/[commemorations]/[transferred_*] difference traceable to this
+   tag anywhere in the domain -- see the task report. *)
+(* SOURCE NOTE on the three literals below (corrected, fix-round review):
+   each is the Missal's own RUNNING HEADER for that Office, which is the
+   convention every other Latin name in this file already follows
+   ([holy_family_sunday], [holy_name_sunday]). Counted across both
+   photographic scans:
+     "Feria V in Cena Domini"                heading FERIA QUINTA IN CENA
+                                             DOMINI; running header 1:1
+     "Feria VI in Passione et Morte Domini"  heading FERIA SEXTA / IN
+                                             PASSIONE ET MORTE DOMINI;
+                                             running header 1:1. NOT
+                                             "Feria VI Parasceve", which
+                                             occurs ZERO times as a title in
+                                             either scan -- every occurrence
+                                             of Parasceve is inside the
+                                             Johannine Passion text. RG
+                                             132(a) writes "feriae VI in
+                                             Passione et Morte Domini".
+     "Sabbato sancto"                        heading SABBATO SANCTO (1x);
+                                             running header "Sabbato sancto"
+                                             28x / 30x.
+   The last was previously shipped as "Sabbato Sancto", a third casing
+   attested in NEITHER scan -- it appears only in the electronic
+   transcription's own table of contents, i.e. the source this project's
+   methodology rule deprecates -- while the comment called it "both
+   photographic scans, word for word". Recased to the running-header form
+   the other names use. *)
+let triduum_names = function
+  | -3 -> Some (Colitur_kernel.Names.of_list [ (Colitur_kernel.Lang.of_string_exn "la", "Feria V in Cena Domini") ])
+  | -2 ->
+      Some
+        (Colitur_kernel.Names.of_list
+           [ (Colitur_kernel.Lang.of_string_exn "la", "Feria VI in Passione et Morte Domini") ])
+  | -1 -> Some (Colitur_kernel.Names.of_list [ (Colitur_kernel.Lang.of_string_exn "la", "Sabbato sancto") ])
+  | _ -> None
+
 let same a b = Date.compare a b = 0
 
 (* Named temporal days: the I-class feasts of the Lord (RG 91 entries 1 and 3),
@@ -731,7 +822,16 @@ let temporal d =
                         Printf.sprintf "ef-%s-%d-%s" (season_slug_word s)
                           (Option.value week_n ~default:0) (weekday_word d)
                       in
-                      build ~season:s ~slug ~colour ~rank:(ferial_rank d s) ~week:week_n ())))
+                      (* [triduum_names]'s own citation above: identity only,
+                         for the three days of the Sacred Triduum -- every
+                         other ferial day here stays unnamed, subject
+                         Temporal, as before. *)
+                      let subject, names =
+                        match triduum_names (days_between easter d) with
+                        | Some names -> (Colitur_kernel.Subject.Lord, names)
+                        | None -> (Colitur_kernel.Subject.Temporal, Colitur_kernel.Names.empty)
+                      in
+                      build ~subject ~names ~season:s ~slug ~colour ~rank:(ferial_rank d s) ~week:week_n ())))
 
 (* Independent restatement of [named]'s fixed and Easter-relative dates,
    paired with the slug each should carry, for civil year [y]. Deliberately