fix(ef): check RG 24/25's ferial invariant instead of asserting it

rubrics_ef.ml's Creed check excluded feriae from 475(b)/(c)/(e) via an
explicit test for feria I classis (Ash Wednesday, Holy Week) and vigils
only. RG 24/25's feriae II and III classis (Advent 17-23 December, the
Advent/Lent/September Ember sets, the numbered Lenten/Passiontide
ferias) were excluded by no check at all, correct today only because of
an unstated Temporal_ef property (no ferial-origin office it builds
carries subject Lord/Bvm or an apostle-list slug). A comment read as if
this were established "by construction of the two exclusions
immediately above", which overclaimed: those two exclusions cover feria
I classis only.

Corrected the comments to name RG 24/25 explicitly, state what is and
is not checked, and cite where the real guarantee comes from. Added a
test that sweeps Temporal_ef.temporal across a century (1583-1682),
asserting the invariant directly against every ferial-origin day found,
with its own coverage counters confirming the span actually reaches
Advent 17-23, all three non-Whitsun Ember sets, and Lenten/Passiontide
ferias. The first run of the test found a real gap in its own
population filter (RG 17(a)'s 2 January Holy Name fallback, a genuine
feast sitting outside Temporal_ef.named for an architectural reason),
fixed by naming that date explicitly rather than narrowing the span.

Proved the test has teeth by mutation: forcing the ferial builder's
default subject to Lord reddened it (and 24 other tests, expected
collateral from an intentionally broad mutation) before being reverted.

No production logic changed -- only comments in rubrics_ef.ml. day,
readings and rubrics output confirmed byte-identical against the
pre-fix binary for four spot years across the domain. Also corrects a
stale test-case count in a prior task report (18 in the array, not the
19 recorded there); the array now genuinely holds 19.

1 files changed, 61 insertions, 9 deletions

diff --git a/lib/rites/rite_ef/rubrics_ef.ml b/lib/rites/rite_ef/rubrics_ef.ml
index eef86cb..6345399 100644
--- a/lib/rites/rite_ef/rubrics_ef.ml
+++ b/lib/rites/rite_ef/rubrics_ef.ml
@@ -160,7 +160,48 @@ let creed ~(temporal : (Vocab_ef.season, Vocab_ef.rank) Temporal.t)
        liturgical action has no Mass in the 1955-restored Holy Week to
        begin with, so the question is moot there independent of this
        check -- but this structural test correctly excludes it too, since
-       it is also named in RG 23(b).) *)
+       it is also named in RG 23(b).)
+
+       RG 24-25 (immediately following, same Caput IV) name TWO MORE
+       ferial classes this branch does not reach: feriae II classis (RG
+       24 -- the Advent ferias 17-23 December, and the Quatuor Temporum
+       sets of Advent, Lent and September) and feriae III classis (RG 25
+       -- the numbered Lenten/Passiontide ferias from the Thursday after
+       Ash Wednesday to the Saturday before Passion Sunday II, and the
+       un-Embered Advent ferias to 16 December). NEITHER is excluded by a
+       check anywhere in this module -- this branch and RG 33's vigil
+       branch immediately below are the whole of what [creed] tests
+       before falling through to 475(b)/(c)/(e)'s own rank/subject/slug
+       guards. They do not need an explicit exclusion of their own for
+       475(b): temporal_ef.ml's own [ferial_rank] never returns [Class1]
+       for them (only Ash Wednesday and Holy Week do, RG 23's own population,
+       already excluded above), so that branch is unreachable for them
+       regardless of anything checked here. But RG 24's own II-class set
+       DOES reach 475(c)'s [Class2] guard below, and 475(e)'s
+       apostle-slug guard carries no rank floor at all, so both classes
+       genuinely reach a live branch of this function. Getting [false]
+       there is NOT established by this exclusion, or by any check in
+       this file: it rests on an unstated property of {!Temporal_ef} --
+       every ferial-origin office it builds carries [subject = Temporal]
+       and an "ef-"-prefixed slug, never [Lord]/[Bvm] or a name on
+       {!creed_apostle_slugs}. Verified directly in temporal_ef.ml: the
+       Ember/Rogation/generic-ferial branches all go through [build]'s
+       own default [subject = Temporal], with exactly two documented
+       exceptions, neither able to reach a live branch below -- the
+       Sacred Triduum ([subject = Lord], but [Class1], already excluded
+       above) and the votive Office of the BVM on Saturday, RG 91 entry
+       27 ([subject = Bvm], but [Class4], never satisfying 475(c)'s own
+       [Class2] guard).
+
+       (CORRECTED, review fix: this comment, and 475(b)'s own immediately
+       below, previously read as though "the two exclusions immediately
+       above" disposed of ferias in general -- they dispose of feria I
+       classis only. RG 24/25's own higher classes were excluded by NO
+       check, an unstated-invariant gap now named here rather than
+       silently relied on: test/test_rubrics_ef.ml's own ferial-invariant
+       sweep now asserts the Temporal_ef property above directly against
+       real output, so a future change that broke it would fail that
+       test rather than silently changing the Creed.) *)
     n = -46 || (n >= -6 && n <= -1)
   then false
   else if
@@ -183,13 +224,17 @@ let creed ~(temporal : (Vocab_ef.season, Vocab_ef.rank) Temporal.t)
   then false
   else if
     (* RG 475(b): "in festis I classis". Genuine feasts only, by
-       construction of the two exclusions immediately above (feriae,
-       vigils) -- every remaining [Class1] candidate reaching this branch
-       is a real festum: the Nativity, Epiphany, Ascension, Corpus Christi,
-       the Sacred Heart, Christ the King, a I-class sanctoral feast (the
-       Assumption, the Immaculate Conception...), or a I-class Sunday
-       (already [true] above via 475(a), so this branch is never the FIRST
-       to grant those a [true], only ever redundant with it). *)
+       construction of the two exclusions immediately above (feria I
+       classis -- Ash Wednesday and Holy Week, the only feriae that are
+       ever [Class1]; RG 24/25's II- and III-class feriae are a different
+       population and never reach this rank at all, see the RG 23
+       comment's own note above -- and vigils) -- every remaining
+       [Class1] candidate reaching this branch is a real festum: the
+       Nativity, Epiphany, Ascension, Corpus Christi, the Sacred Heart,
+       Christ the King, a I-class sanctoral feast (the Assumption, the
+       Immaculate Conception...), or a I-class Sunday (already [true]
+       above via 475(a), so this branch is never the FIRST to grant those
+       a [true], only ever redundant with it). *)
     observed.Celebration.rank = Vocab_ef.Class1
   then true
   else if
@@ -207,7 +252,14 @@ let creed ~(temporal : (Vocab_ef.season, Vocab_ef.rank) Temporal.t)
        ships [subject = Saint] instead -- {!Precedence_ef.marian_slugs} is
        the list built (and, here, reused rather than re-derived) precisely
        because the [subject] field cannot be trusted alone for this
-       question; see its own citation in precedence_ef.mli. *)
+       question; see its own citation in precedence_ef.mli.
+
+       This [Class2] guard is also the one live branch RG 24's own
+       II-class feriae (Advent 17-23, the Advent/Lent/September Ember
+       sets) genuinely reach -- the RG 23 comment above (this file, the
+       [n = -46 ...] branch) has the full account of why they still come
+       out [false] here: an unstated Temporal_ef property, checked by a
+       test, not a guard in this file. *)
     observed.Celebration.rank = Vocab_ef.Class2
     && (observed.Celebration.subject = Subject.Lord
        || observed.Celebration.subject = Subject.Bvm