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.

0 files changed, 0 insertions, 0 deletions