feat(of-lectionary): hand-author the Christmas Day Mass, close the gap

colitur readings --rite of printed "- | -" on 25 December every year
-- lectio's own 988 keys never included the Christmas DAY Mass at
all, only the Vigil (already correctly noted, but left unfilled, in
tools/bootstrap_lectionary_of.ml's own named_overrides comment).

Sourced, not guessed: docs/research/of/olm-1981-ocr.txt:4513-4520,
"16 Ad Missam in die", the same primary authority this module already
cites for the cycle rules. First reading and Gospel only, matching
this file's own scope everywhere else (First/Gospel is the kernel's
own boundary, I7, a separate deferred task) -- Isaiah 52:7-10 / John
1:1-18 (OLM's own LONGER form; the file's LINEAGE section already
discloses that short/long-form choices are not modelled anywhere in
this data, so this is an application of an existing limitation, not a
new one).

Injected via a new hand_authored table in the generator, merged into
entries before assert_reachable/Lectionary.of_entries -- there is no
ini section to derive this from. One new lookup_any call (readings'
own existing temporal-slug fallback, unmodified) now resolves BOTH the
formulary and the citations for 25 December from the same entry, so
both halves of the "citations-unresolved"/"formulary" gap close
together, not just the citation half.

Verified across the WHOLE domain, not assumed: test_validate_of.ml's
exhaustive sweep (COLITUR_EXHAUSTIVE_SWEEP=1, all 8 416 years) now
asserts the Nativity gap fires on NONE of them, down from all 8 416
before this fix -- and is kept as a live, dedicated "must never recur"
counter rather than deleted. test_rite_of.ml's landmark-year check and
test_lectionary_of.ml's 2026 coverage pins are updated the same way
(the unresolved-day set that used to be pinned as {25 December} is now
pinned as empty, not merely a count going to zero). A concrete golden
pin (test_golden_of.ml) locks the exact citations through the full
resolved pipeline. data/of/lectionary.sexp regenerated (771 entries,
was 770); its own SHA-256 re-pinned.

make check (COLITUR_EXHAUSTIVE_SWEEP=1 dune test --force, unpiped,
foreground): exit 0, 895 tests, ~536s.

1 files changed, 8 insertions, 6 deletions

diff --git a/data/of/lectionary.sexp b/data/of/lectionary.sexp
index 8cc1d63..437cada 100644
--- a/data/of/lectionary.sexp
+++ b/data/of/lectionary.sexp
@@ -52,11 +52,11 @@
 ; SHA-256: f0b527aef58b93e6ccdfbeafe52b340ed2a9d7d72805bf5083e3da04b080123c
 ; 988 ini sections (988 expected) -> 438 resolved (base, cycle-shape) pairs -> 435 colitur slugs mapped, 3 ini bases genuinely excluded (structurally
 ; unreachable -- see [excluded_bases]), 0 ini bases genuinely unmapped
-; (no pattern, no override, no matching sanctoral slug) -> 770 emitted
+; (no pattern, no override, no matching sanctoral slug) -> 771 emitted
 ; lectionary entries.
 ;
 ; COVERAGE, BOTH DIRECTIONS (Step 1 of this task's own brief):
-;   (1) Temporal-day gap: of the 365 days of civil year 2026, 1 produce a
+;   (1) Temporal-day gap: of the 365 days of civil year 2026, 0 produce a
 ;       Rite_of.Temporal_of slug with NO entry in this file (tried the
 ;       date-keyed route first, then flat, then both the Sunday- and
 ;       weekday-cycle letter suffixes -- the same order
@@ -76,8 +76,8 @@
 ;       OLM norms working as designed for a saint with no proper of
 ;       their own, not a gap in this data.
 ;   (4) Citation-siglum conversion (fix wave I2, 2026-08-26 review): of
-;       1540 emitted (First, Gospel) citation fields, 41 distinct
-;       references (out of the full 1540) do not parse -- every one a
+;       1542 emitted (First, Gospel) citation fields, 41 distinct
+;       references (out of the full 1542) do not parse -- every one a
 ;       hyphen range that crosses a chapter boundary ("2:29-3:6"), a
 ;       {!Colitur_citation.Parse.t} shape this parser's [part]/
 ;       [verse_range] types do not represent, deliberately not built
@@ -134,9 +134,8 @@
 ;   Wisdom 11:22-12:2
 ;   Wisdom 2:23-3:9
 ;   Wisdom 7:22b-8:1
-; Temporal_of slugs (2004-2051) with no lectionary entry (1, informational --
+; Temporal_of slugs (2004-2051) with no lectionary entry (0, informational --
 ; most are the Christmas-season/late-Advent date-vs-weekday gap named above):
-;   of-nativity
 ((all-saints
   (((part First) (reference "Revelation 7:2-4,9-14"))
    ((part Gospel) (reference "Mat 5:1-12"))))
@@ -857,6 +856,9 @@
  (of-mary-mother-of-god
   (((part First) (reference "Numbers 6:22-27"))
    ((part Gospel) (reference "Luke 2:16-21"))))
+ (of-nativity
+  (((part First) (reference "Isaiah 52:7-10"))
+   ((part Gospel) (reference "John 1:1-18"))))
  (of-nativity-vigil
   (((part First) (reference "Isaiah 62:1-5"))
    ((part Gospel) (reference "Mat 1:18-25"))))