fix(ef): ferias after the Ascension repeat its own Mass, not a Sunday's

Ascension has no octave under the 1960 rubrics -- confirmed structurally:
the Proprium de Tempore's own table of contents runs straight from "In
Ascensione Domini" to "Dominica post Ascensionem" with no per-feria
headings in between. Step 3 of the reading chain therefore fell through
to Preceding_sunday on every unoccupied weekday in that stretch, walking
each one back to the 5th or 6th Sunday after Easter's own citation.

The Missal's own Proprium de Tempore carries an explicit marginal rubric
immediately after the Ascension's Mass propers, before "Dominica post
Ascensionem" begins: "Diebus a feria VI post Ascensionem usque ad feriam
VI ante vigiliam Pentecostes inclusive, dicitur Missa de festo
Ascensionis, cum Gloria et praefatione de Ascensione, sine Credo et
Communicantes proprio" -- every feria without its own proper, from the
Friday after the Ascension through the Friday before the Vigil of
Pentecost, repeats the Ascension's own Mass. RG 490(b) corroborates
independently: it assigns the Ascension preface "tamquam de Tempore"
across that identical window, which only makes sense if the Mass
actually repeated there is the Ascension's, not a numbered Sunday's
(whose own Mass would carry no need for a preface override at all).

Witnessed directly, not only inferred from the rubric: the LMS Ordo
prints "Mass of the Ascension" literally on every affected day across
all three of its fixture windows, in BOTH the tail of Ascension's own
week and the following week -- ruling out the alternative reading (that
the second week instead resumes "Dominica post Ascensionem"'s own Mass,
which a first pass over the FIUV Ordo's own week-labelled titles could
suggest at a glance; its own [praef] field for the same two dates
independently reads "Ascensionis", resolving the apparent conflict).

Implemented as data, not logic, matching this codebase's own established
precedent for the identical RG 299 shape (the week after Trinity Sunday,
data/ef/lectionary.sexp's [trinity_week_entries]): six new hand-authored
entries, [ascension_week_entries] in tools/bootstrap_lectionary.ml,
regenerated against a git-pinned copy of lectio's own source ini (SHA-256
verified unchanged) so the regeneration carries no unrelated drift. The
window's two Saturdays are deliberately excluded -- RG 78's votive Office
of Our Lady on Saturday always wins an otherwise-unoccupied Class4
Saturday first, before step 2 (this fix's own entry point) is ever
reached, so an entry for either slug would be dead data.

Blast radius measured in-process across the full 1583-9999 domain
(throwaway probe, not committed): 16 350 days total across the six
slugs, every one resolved via step 2 (Own_slug), zero anomalies, and the
window's two Saturdays confirmed to contribute zero hits via this cause
across the whole domain, corroborating the RG78-interception reasoning
by direct sweep.

Closed L2 in data/ef/expected-divergences-lms.sexp. New cited entries:
C41 in data/ef/expected-divergences.sexp (95 of 16801 rows, 2005-2050 --
lectio has no equivalent rubric and still walks these ferias back);
M31 in data/ef/expected-divergences-missalemeum.sexp (3 rows in the
2026-2027 window, plus the same shape independently reconfirmed in the
2035 and 2038 live-capture windows) -- missalemeum, Divinum Officium's
lineage, still gives the same wrong answer colitur itself used to give,
which is why these rows used to agree with M18's shape and now escape it
(M18 373 -> 370, the same mechanism M23-M27 established when the
citation axis was first built).

Golden pin: 2031-05-23, the exact date the bug report was filed against.

Mutation-tested: reverting data/ef/lectionary.sexp alone (a git-diff
capture/restore, not a source-code revert, since the fix is data) reddens
19 tests across the differential, both oracle fixtures, all three LMS
Ordo windows, the golden pin, the lectionary unit test and every Render
golden template; restored and reconfirmed green (681 tests; 683 under
COLITUR_EXHAUSTIVE_SWEEP=1, ~175s).

1 files changed, 70 insertions, 0 deletions

diff --git a/tools/bootstrap_lectionary.ml b/tools/bootstrap_lectionary.ml
index 7df290b..1e9b8ed 100644
--- a/tools/bootstrap_lectionary.ml
+++ b/tools/bootstrap_lectionary.ml
@@ -637,6 +637,75 @@ let trinity_week_entries =
        lectionary has been bitten by before. *)
     [ "monday"; "tuesday"; "wednesday"; "friday"; "saturday" ]
 
+(* RG 299's own escape clause, second instance (celebrant-rubrics-phase1,
+   Bug 2, 2026-08-22). The Proprium de Tempore carries an explicit
+   marginal rubric immediately after the Ascension's own Mass propers,
+   before "Dominica post Ascensionem" begins (scan1.txt:20749-20754, both
+   scans corroborate): "Diebus a feria VI post Ascensionem usque ad
+   feriam VI ante vigiliam Pentecostes inclusive, dicitur Missa de festo
+   Ascensionis, cum Gloria et praefatione de Ascensione, sine Credo et
+   Communicantes proprio" -- on the days from the Friday after the
+   Ascension until the Friday before the Vigil of Pentecost INCLUSIVE,
+   the MASS OF THE FEAST OF THE ASCENSION is said (with the Gloria and
+   the Ascension preface, without the Creed and the proper
+   Communicantes). Corroborated independently by RG 490(b) (LT.txt:3981-
+   3985), which assigns the Ascension preface "tamquam de Tempore" to
+   every Mass in that same window lacking a proper preface of its own --
+   consistent only if the Mass repeated there is the Ascension's own,
+   not a numbered Sunday's (which would need no preface override at
+   all).
+
+   Witnessed directly, not merely inferred from the rubric: the LMS Ordo
+   prints "Mass of the Ascension" literally, across all three fixture
+   windows this project has built (2023-2024: 1 day; 2024-2025: 3 days;
+   2025-2026: 2 days -- data/ef/expected-divergences-lms.sexp's own L2,
+   closed by this entry), on EVERY affected day in BOTH the remainder of
+   Ascension's own week and the following week, not only the first --
+   ruling out the alternative reading that the second week instead
+   resumes "Dominica post Ascensionem"'s own Mass. The FIUV Ordo's own
+   title convention for these days (2025-2026 fixture, 2026-05-21/22,
+   "Feria V/VI Dom. post Ascensionem, De ea") could look like the
+   opposite at a glance -- it is not: FIUV's title names which WEEK a
+   feria belongs to (a bookkeeping label, the same role colitur's own
+   week-numbered slug plays), while its own [praef] field for those
+   exact two days independently reads "Ascensionis", confirming the Mass
+   actually said is still the Ascension's, exactly as the marginal
+   rubric and RG 490(b) both require.
+
+   The window's two Saturdays (Easter+41, Easter+48) are DELIBERATELY
+   NOT given entries here. Easter+48 is the Vigil of Pentecost, a named
+   day with its own Mass ({!Rite_ef.Temporal_ef.named}), outside the
+   rubric's own "usque ad feriam VI" upper bound. Easter+41 is an
+   ordinary IV-class Saturday, so {!Rite_ef.Lectionary_ef.readings}'s
+   own RG 78/RG 309(a) votive-Mass-of-Our-Lady-on-Saturday branch ALWAYS
+   intercepts it before step 2 is ever reached (checked directly:
+   [is_bvm_saturday_office] fires unconditionally on any unoccupied
+   Class4 Saturday, which every ordinary Paschaltide Saturday is) -- an
+   entry for either Saturday slug would be dead data that
+   [assert_reachable] cannot catch (both slugs it would name ARE real,
+   reachable Temporal_ef offices; the shadowing happens one level up, in
+   [readings]' own step ordering, not in slug reachability).
+
+   Six ferias, matching the Ascension's own citation already given above
+   (Act. 1, 1-11 / Marc. 16, 14-20, scan1.txt:20701-20730,
+   [ef-ascension]'s own entry): the one remaining non-Saturday day of
+   Ascension's own week (Easter+40) and the five weekdays of the
+   following week (Easter+43..47), bounded above by that week's own
+   Friday -- the Saturday after it is the Vigil of Pentecost, named,
+   never reaching this table. *)
+let ascension_week_citations = pair ~first:"Acts 1:1-11" ~gospel:"Mark 16:14-20"
+
+let ascension_week_entries =
+  List.map
+    (fun slug -> (slug_or_die slug, ascension_week_citations))
+    [ "ef-easter-6-friday";
+      "ef-easter-7-monday";
+      "ef-easter-7-tuesday";
+      "ef-easter-7-wednesday";
+      "ef-easter-7-thursday";
+      "ef-easter-7-friday"
+    ]
+
 let epiphanytide_opening_entries =
   List.concat_map
     (fun (family, wds, cs) ->
@@ -789,6 +858,7 @@ let () =
     translated @ vigil_entries @ holy_week_entries @ passion_tuesday_entry
     @ ember_saturday_corrections @ nativity_octave_entries @ holy_name_entries
     @ epiphanytide_opening_entries @ trinity_week_entries @ movable_feast_entries
+    @ ascension_week_entries
   in
   assert_reachable entries;
   let lect =