fix(ef): RG 112(d) excludes a same-BVM commemoration (fix round 1, F1)

The BVM Saturday Office is itself "de B. Maria Virg."; RG 112(d) (Caput
XVI, "De Commemorationibus") excludes another commemoration whose own
oration invokes the SAME BVM's intercession. our-lady-of-mt-carmel (16
July, Commemoration_only) was wrongly admitted as an ordinary
commemoration alongside the Office on every 16-July-Saturday -- its own
collect explicitly invokes "her" (eius) patronage, and both photographic
scans print a rubric anticipating exactly this collision (an either/or
of Mass texts, not a joint commemoration).

Precedence_ef gains marian_slugs (a closed, hand-verified list of
sanctoral slugs that are themselves feasts of the BVM) and is_bvm_office
(true for subject = Bvm OR a marian_slugs member -- the disjunction is
load-bearing: the Office is identified only by subject, since its own
slug is deliberately reused from the ordinary ferial fallback; Mt Carmel
is identified only by the list, since its own subject tag is Saint, not
Bvm). disposition gains a new branch, checked before the pre-existing
Commemoration_only catch-all, since the one live witness is
Commemoration_only and that branch's own "always Commemorate" had no
exception for this shape.

Checked exhaustively against every Marian-named sanctoral entry: only
Commemoration_only-status entries can ever reach this branch live (a
Feast-status one always wins outright instead of losing). Of the two
such entries in the data, only Mt Carmel is reachable --
our-lady-of-ransom (24 September) is provably unreachable: 24 September
falling on a Saturday forces 1 September to a Thursday, which by
construction makes 24 September the September Ember Saturday, Class2,
every time, not a sampled coincidence.

Re-measured against the full pre-change binary: the original 75,853-day
blast radius is unchanged in total, splitting into 74,633 colour-only +
1,220 colour+comms (16-July Saturdays). Mutation-tested: exactly 3 new
tests redden, nothing else.

1 files changed, 167 insertions, 9 deletions

diff --git a/lib/rites/rite_ef/precedence_ef.ml b/lib/rites/rite_ef/precedence_ef.ml
index 5a2d307..302df98 100644
--- a/lib/rites/rite_ef/precedence_ef.ml
+++ b/lib/rites/rite_ef/precedence_ef.ml
@@ -364,14 +364,21 @@ let band (ctx : Vocab_ef.season Precedence.context) (c : Vocab_ef.rank Precedenc
   else if is_temporal && rank = Class3 && season = Advent then 250
     (* 26: III-class vigils (St Lawrence). *)
   else if rank = Class3 && is_vigil then 260
-    (* 27: Office of the BVM on Saturday -- every otherwise-unoccupied IV-class
-       Saturday, per the historical default that fills it; ordinary Mass
-       propers still make Rogation Mon/Tue/Wed proper without changing the
-       Office (RG 88, see temporal_ef.ml's [temporal]), so those never carry
-       this entry unless they happen to fall on the Saturday itself. Excludes
-       vigils for the same reason 11-13/14/16/19/20/23/24 do: RG 91 has no
-       IV-class vigil at all (RG 91's own vigil list, §4 "Vigils",
-       stops at III class), so one would be an anomaly, not this entry. *)
+    (* 27: Office of the BVM on Saturday -- RG 78 (Caput IX, "De sancta Maria
+       in sabbato"), both photographic scans and the electronic
+       transcription, word for word (docs/research/rules-register.md §4/§6.4;
+       Rite_ef.Temporal_ef's own [bvm_saturday_names] citation has the full
+       argument): "78. In sabbatis, in quibus occurrit Officium de feria IV
+       classis, fit de sancta Maria in sabbato" -- on Saturdays on which the
+       Office of a IV-class feria occurs, [the Office] is made of Holy Mary
+       on Saturday instead. Every otherwise-unoccupied IV-class Saturday
+       reaches this branch; ordinary Mass propers still make Rogation
+       Mon/Tue/Wed proper without changing the Office (RG 88, see
+       temporal_ef.ml's [temporal]), so those never carry this entry unless
+       they happen to fall on the Saturday itself. Excludes vigils for the
+       same reason 11-13/14/16/19/20/23/24 do: RG 91 has no IV-class vigil at
+       all (RG 91's own vigil list, §4 "Vigils", stops at III class), so one
+       would be an anomaly, not this entry. *)
   else if is_temporal && (not is_vigil) && rank = Class4 && weekday = Date.Sat then 270
     (* 28: IV-class ferias -- the unqualified catch-all (temporal_ef.ml's own
        comment on [ferial_rank] cites the same primary text, "Feriae IV
@@ -380,6 +387,148 @@ let band (ctx : Vocab_ef.season Precedence.context) (c : Vocab_ef.rank Precedenc
   else if (not is_vigil) && rank = Class4 then 280
   else unclassified
 
+(* RG 112(d) (Caput XVI, "De Commemorationibus"), the BVM half, fix round 1
+   of the ef-bvm-saturday task (coordinator finding F1) -- both photographic
+   scans, word for word (docs/research/rules-register.md §4's own RG 112
+   entry already carries this sub-clause, unbuilt until this fix): *"item,
+   Officium, Missa aut commemoratio de B. Maria Virg. aut de aliquo Sancto
+   vel Beato excludit aliam commemorationem aut orationem in qua eiusdem B.
+   Mariae Virg., vel Sancti aut Beati intercessio imploretur: quod tamen non
+   valet de oratione dominicae vel feriae, in qua fit invocatio eiusdem
+   Sancti."* -- the Office, Mass or commemoration OF the Blessed Virgin Mary
+   (or of some Saint or Blessed) excludes ANOTHER commemoration or oration
+   in which the intercession OF THE SAME BVM (or Saint or Blessed) is
+   invoked -- which however does not hold of the oration of a Sunday or
+   feria, in which invocation of the same Saint occurs.
+
+   Found live by the fix-round review: the BVM Saturday Office (RG 91 entry
+   27, [temporal_ef.ml]'s own [bvm_saturday_names]) is itself "de B. Maria
+   Virg." -- so when it is observed, RG 112(d) excludes any OTHER admitted
+   candidate whose own oration invokes the SAME BVM's intercession, not
+   merely commemorates her in passing. Real live witness: 16 July,
+   "our-lady-of-mt-carmel" (data/ef/sanctoral.sexp, Class3,
+   [Commemoration_only]) falls on a Saturday 8 times in the 2005-2050
+   fixture alone; its own collect, both photographic scans, word for word
+   (Caput "Die 16 iulii, Beatae Mariae Virginis de Monte Carmelo,
+   Commemoratio"): *"...concede propitius; ut, cuius hodie Commemorationem
+   solemni celebramus officio, EIUS muniti praesidiis, ad gaudia sempiterna
+   pervenire mereamur"* -- "her" ("eius") -- grant, we beseech Thee, that we,
+   fortified by HER patronage, whose Commemoration we solemnly celebrate
+   today, may be permitted to arrive at everlasting joys -- an explicit
+   invocation of the SAME BVM's own intercession/patronage, precisely RG
+   112(d)'s own trigger.
+
+   The exception clause ("non valet de oratione dominicae vel feriae") does
+   NOT rescue this: RG 91 lists entry 27 as its own table row, separate from
+   entry 28's "feriae IV classis" -- this Office is neither a Sunday nor,
+   once RG 78 has substituted it in, a plain "feria" in Caput IV's own
+   sense (RG 21: "Nomine feriae intelleguntur singuli dies hebdomadae" --
+   an ordinary weekday's OWN office, which RG 78 replaces, not merely
+   supplements).
+
+   ALSO found on the very same page, both photographic scans, word for
+   word, confirming the collision is real and rubric-anticipated (not
+   merely this codebase's own inference): *"Si Commemoratio B. Mariae
+   Virg. de Monte Carmelo venerit in sabbato, Missa dici potest aut de
+   sancta Maria in sabbato, aut propria de Commemoratione B. Mariae Virg.
+   de Monte Carmelo."* -- if the Commemoration of the BVM of Mount Carmel
+   falls on a Saturday, the Mass MAY be said EITHER of Holy Mary on
+   Saturday OR properly of the Commemoration of the BVM of Mount Carmel --
+   an explicit EITHER/OR between two MASS TEXTS, not an instruction to
+   commemorate one in the other's Office. Read together with RG 112(d):
+   the OFFICE question (is Mt Carmel commemorated at all) and the MASS
+   question (which of the two propers is said that day) are two different
+   questions -- RG 112(d) answers the first (excluded); this rubric answers
+   the second, and is a Mass-propers selection detail of exactly the same
+   kind as the I-V numbered cycle (RG 309(a)) [bvm_saturday_names]'s own
+   citation already puts out of scope for the SAME reason (colitur computes
+   no citations/readings at all yet, Plan 4) -- not modelled here either.
+
+   [marian_slugs] is a CLOSED, HAND-VERIFIED list, not a claim to have read
+   every one of these entries' own Latin orations on the scan (only
+   Mt Carmel's, quoted above, was actually verified against the primary
+   text for this fix) -- built from data/ef/sanctoral.sexp's own [names.en]
+   field, restricted to entries that are themselves a feast/commemoration
+   OF the Blessed Virgin Mary in her own right (never merely a feast of
+   someone else that happens to mention her -- "St. Anne, Mother of the
+   Blessed Virgin", "St. Joseph, Spouse of the Bl. Virgin Mary", "St.
+   Anthony Mary Claret" and similarly-named entries are deliberately
+   EXCLUDED, checked one by one). This is the SAME modelling simplification
+   {!disposition}'s own pre-existing RG 112(a) branch already makes for
+   "eiusdem Divinae Personae" (read as simply "both [subject = Lord]",
+   that branch's own comment: "safe at today's data's own granularity") --
+   here read as "titled a feast of the BVM", not verified oration-by-
+   oration, and said so explicitly rather than overclaimed. TWO entries
+   found and deliberately EXCLUDED after individual consideration, not
+   merely omitted: "dedication-of-the-basilica-of-st-mary-major" (5
+   August, Class3, Feast) -- a DEDICATION feast (of the building, "In
+   Dedicatione S. Mariae ad Nives"), whose own oration could not be found
+   in either scan under this exact heading to confirm it invokes her
+   intercession the same way an ordinary Marian commemoration does, so left
+   out per this project's "a wrong citation is worse than a missing one"
+   rule; and "purification-of-the-blessed-virgin-mary" (2 February,
+   Class2), already deliberately tagged [subject = Lord] by an earlier
+   task's own ruling (register §6.0, following the oracle's Sunday-
+   displacing treatment) for an unrelated reason -- its own RG 112(a)
+   Lord-vs-Lord exclusion already covers it against another Lord-subject
+   winner, and at Class2 it can never lose to a Class4 candidate in the
+   first place (this or any other), so including or excluding it here has
+   no live consequence either way; excluded for consistency with the
+   earlier ruling rather than silently overriding it.
+
+   What this rule COVERS: any admitted candidate on {!marian_slugs}' own
+   closed list, or tagged [subject = Bvm], losing to a WINNER that is
+   itself either {!marian_slugs}-listed or [subject = Bvm] -- currently
+   live only for the BVM Saturday Office (subject-tagged, its own slug
+   deliberately NOT on this list, {!bvm_saturday_names}'s own "Slug"
+   citation in temporal_ef.ml) as winner against Mt Carmel as loser, plus
+   (checked, not live: 24 September, "our-lady-of-ransom", the ONLY other
+   {!Celebration.status.Commemoration_only} Marian entry in the data) --
+   PROVEN structurally unreachable: 24 September falling on a Saturday
+   forces 1 September to be a Thursday (23 days = 3 weeks 2 days earlier),
+   which by {!third_sunday_of_september}'s own construction makes 24
+   September the September Ember Saturday EVERY time, RG 91 entry 18
+   (Class2), always outranking entry 27 -- not a sampled coincidence, an
+   exact day-of-week identity, checked against several sample years above
+   before being generalised. What this rule does NOT cover, stated
+   plainly: a hypothetical non-Marian-titled saint whose own oration
+   happens to invoke the BVM's intercession in passing (RG 112(d)'s own
+   text does not restrict itself to Marian-TITLED commemorations) -- no
+   oration text is stored anywhere in this codebase to detect that, and
+   none is guessed at here. Also does not cover RG 112(d)'s OTHER half (two
+   commemorations of the SAME non-BVM saint) -- unbuilt, unaffected by this
+   fix, register §4/§6 already tracks it as open.
+
+   Checked for what this fix does NOT change: {!Precedence.resolve} holds
+   [Commemoration_only] candidates out of the WINNER contest entirely, so
+   Mt Carmel could never have been [observed] either before or after this
+   fix -- only its own admission AS a commemoration changes. Verified live
+   against real 2033/2005 data (both years 16 July is a Saturday): before
+   this fix, [comms] included "our-lady-of-mt-carmel:ordinary"; after,
+   [comms] is empty and the omitted list carries it with reason "omitted:
+   yielded to a higher day", the same generic reason every other [Omit]
+   disposition in this function produces. *)
+let marian_slugs =
+  [ "annunciation-of-the-blessed-virgin-mary";
+    "assumption-of-the-blessed-virgin-mary";
+    "immaculate-conception-of-the-blessed-virgin-mary";
+    "immaculate-heart-of-mary";
+    "maternity-of-the-blessed-virgin-mary";
+    "most-holy-name-of-mary";
+    "nativity-of-the-blessed-virgin-mary";
+    "our-lady-of-lourdes";
+    "our-lady-of-mt-carmel";
+    "our-lady-of-ransom";
+    "our-lady-of-the-rosary";
+    "presentation-of-the-blessed-virgin-mary";
+    "queenship-of-the-blessed-virgin-mary";
+    "seven-sorrows-of-the-blessed-virgin-mary";
+    "visitation-of-the-blessed-virgin-mary" ]
+
+let is_bvm_office (c : Vocab_ef.rank Precedence.candidate) =
+  c.Precedence.cel.Celebration.subject = Subject.Bvm
+  || List.mem (Slug.to_string c.Precedence.cel.Celebration.slug) marian_slugs
+
 (* Task 8: what happens to the day's LOSING candidate (docs/research/
    rules-register.md §4, "Occurrence" RG 92-95 and "Vigils" RG 33, plus RG
    94; also §6.0/Caput III "De Dominicis" RG 16(a), below). [band] above
@@ -602,7 +751,16 @@ let disposition ~(winner : Vocab_ef.rank Precedence.candidate)
   let open Vocab_ef in
   let cel = loser.Precedence.cel in
   let is_temporal = loser.Precedence.origin = Precedence.Temporal in
-  if cel.Celebration.status = Celebration.Commemoration_only then
+  if is_bvm_office winner && is_bvm_office loser then
+    (* RG 112(d) -- see [marian_slugs]'s own citation above for the full
+       argument. Checked FIRST, even ahead of the [Commemoration_only]
+       branch immediately below, because the one live witness
+       (Mt Carmel, 16 July) IS [Commemoration_only] -- that branch's own
+       "always Commemorate, nothing overrides it" previously had no
+       exception for two commemorations invoking the identical BVM, the
+       exact gap this fix closes. *)
+    Precedence.Omit
+  else if cel.Celebration.status = Celebration.Commemoration_only then
     (* Always -- checked before RG 33's omission and RG 95's transfer so
        neither can override it: a Commemoration_only entry can never win
        (Precedence.resolve holds it out of the band contest entirely, see