test(oracle): fix round 1 -- C30 disclosure, RG 17(a) misattribution, M26 shapes

Three Important findings from coordinator review of 8d1eb25, all fixed.

1. C30's own note claimed its 91-row population "is C25's OWN former
   population, before this task narrowed it" -- false. Independently
   re-derived against the real resolver (pre-fix vs post-fix binary) and
   the lectio fixture: only 44 of the 91 rows were ever in C25 (Wed 6/
   Thu 19/Fri 19, matching C25's own fix-round-3 breakdown exactly); the
   other 47 (all of Monday/Tuesday, plus part of Wednesday/Friday)
   previously matched lectio outright -- both engines independently
   landing on the same wrong value -- and are newly allow-listed only
   because colitur is now right. Rewritten to the same "both engines
   silently agreed on the wrong answer" pattern C33/C34 already used.

2. "Diebus ferialibus" is not RG 17(a) -- RG 17(a) states only the
   day-identity privilege; the ferial-Mass rubrics are Mass-propers
   rubrics, a distinction the register's own §6.3 already drew before
   this task's first pass blurred it in code/allow-list comments. A
   further slip: C31/C32 called their own rubric "RG 17(a)'s own next/
   third sentence" when it is a different rubric block ~230 lines away,
   in Holy Family's (not Holy Name's) own feast propers. Fixed the
   attribution chain throughout tools/bootstrap_lectionary.ml,
   data/ef/expected-divergences.sexp's C29-C34, and (gitignored, outside
   this commit) docs/research/rules-register.md -- closed the §6.3 park,
   added §6.5 recording all four citations with corrected attribution.
   Quotes and line numbers were already right; only the chain of custody
   to RG 17(a) was wrong.

3. M26's own 30 rows classify into two nameable shapes, not "three
   confirmed shapes" with an unexplained 23-row residue that was in fact
   empty: 21 rows are RG 78's own already-documented BVM votive-Mass
   gap; 9 rows are a second, distinct gap -- a week whose own Sunday was
   displaced by a movable named feast (Trinity->Corpus Christi, "Missa
   Dominicae I post Pentecosten"; Christ the King), where the Missal
   requires the displaced Sunday's own Mass to keep informing that
   week's ferias but step 3 walks back to the displacing feast's citation
   instead -- proven directly by colitur's own citation on the Christ-
   the-King rows being literally that feast's own Gospel. verdict open
   unchanged (not fixed here); the shape is now named instead of buried.

Minors: section count corrected 1458->1456 (four places); "exactly one
candidate, zero ambiguous" corrected to "correctness rests on ordering,
not uniqueness" (2 of 1456 sections genuinely yield two candidates,
Holy Saturday's own Lectio, both years); the stale "nothing in layers
3-5 compares citations" claim corrected (only layer 5 still doesn't);
M18's note corrected (five new entries not six; ~18 of its remaining
352 rows only agree now because of this task's own fixes, not "already"
before it); "five" corrected to "six" otherwise-unoccupied Saturdays in
bootstrap_lectionary.ml; scan2 quotes softened where OCR-garbled.

Also done outside the git-tracked files: the step-4 (Commons) coverage
gap is now recorded in data/ef/expected-divergences-missalemeum.sexp's
own header, not only the commit body and the (gitignored) report.

dune test: 358 tests green. COLITUR_EXHAUSTIVE_SWEEP=1 dune test
--force: 359 tests green, 95.7s.

1 files changed, 18 insertions, 5 deletions

diff --git a/test/fixtures/missalemeum-ef-2026-2027.provenance b/test/fixtures/missalemeum-ef-2026-2027.provenance
index d760c9f..33b5566 100644
--- a/test/fixtures/missalemeum-ef-2026-2027.provenance
+++ b/test/fixtures/missalemeum-ef-2026-2027.provenance
@@ -49,11 +49,24 @@ things verified during extraction, not merely assumed: no field collides
 with the "|"/";" delimiters, all 4 multi-Mass days (info is an array on
 2026-11-02, 2026-12-25, 2027-11-02, 2027-12-25) carry an IDENTICAL info
 block (rank/colors/tempora/commemorations/displaced) across every Mass of
-the day, so taking entry[0] throughout (this fixture's own convention)
-loses nothing the comparator or a human auditor needs, and the citation
-extraction itself (all 1 458 Lectio/Evangelium sections across the 728
-days that carry one) yields exactly one unambiguous citation-shaped
-candidate per section -- checked exhaustively, not sampled.
+the day, so taking entry[0] throughout for THOSE fields (this fixture's
+own convention) loses nothing the comparator or a human auditor needs
+there -- CORRECTED, fix round 1 (coordinator review): this is NOT true
+for the citation fields Task 9 added. Christmas (25 December) has three
+genuinely different Masses (Midnight/Dawn/Day) with three different
+Epistle+Gospel pairs; entry[0] is the Midnight Mass, colitur's own
+citation (bootstrapped from lectio) reflects the Day Mass -- a real,
+documented divergence (test_oracle.ml's own M27), not one this
+convention avoids. The citation extraction itself (all 1 456 Lectio/
+Evangelium sections, 728 days x 2) does NOT yield exactly one candidate
+per section either -- CORRECTED, fix round 1: 2 of the 1 456 (Holy
+Saturday's own "Lectio", both years) yield two verse-shaped spans,
+['Col 3:1-4', 'Ps 117, 1'] (the second is the Tractus verse following
+the real citation in the same paragraph). Both rows are still extracted
+correctly because [extract_citation] returns candidates[0] and the real
+citation happens to come first -- correctness rests on ORDERING, not
+uniqueness. See tools/extract_missalemeum_oracle.py's own header for
+the full account of both corrections.
 
 Regenerate with the same commands if the missalemeum snapshot is refreshed
 and the fixture needs updating; do not hand-edit this file or the fixture.