propers: Benedictus antiphons for December's sanctoral entries (9/10)

4 authored fresh (Nicholas, the Immaculate Conception, Damasus, Thomas
of Canterbury), 1 corrected (Lucy -- confirmed sourced from the Roman
rite's raw [Ant 1] rather than a real Monastic 1617 rendering, same
pattern as every month so far). Thomas Apostle, Stephen Protomartyr,
John Apostle, and Holy Innocents already matched the live query as
found -- December's own late feasts (the Christmas Octave content)
turned out much less prone to the Roman/Monastic divergence than
earlier months, presumably because they're old and universal enough
that the two rites never actually diverged on them.

St. Bibiana left honestly missing: Simplex rank, Dec 2 falls within
Advent every tested year 2026-2029, same structural block as St.
Frances of Rome in March -- she can never win her own day outright
under this app's own calendar rules.

This closes out the full sweep: all 109 sanctoral entries with a
propers id have now been checked against a live Monastic query, twelve
months, one at a time. TODO.md has the final tally.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

TODO.md

@@ -163,7 +163,25 @@ saint has the same kind of mismatch.
   authored fresh (All Saints, Clement I, Catherine of Alexandria,
   Silvester Abbot). Martin of Tours already matched the live query as
   found, no change needed.
-- **December (10 saints): not started.**
+- **December (10 total): done, 9 authored/corrected, 1 flagged.** 2
+  corrected (Lucy), 6 authored fresh (Nicholas, Immaculate Conception
+  [minor English fix -- the source's own translation said "her Birth"
+  for a Conception antiphon, an obvious copy-paste leftover from the
+  Nativity-of-the-BVM formula this reuses; corrected, marked draft],
+  Damasus, Thomas of Canterbury). Thomas Apostle, Stephen Protomartyr,
+  John Apostle, and Holy Innocents already matched the live query as
+  found, no change needed. St. Bibiana left `missing`: Simplex rank, and
+  Dec 2 falls within Advent in every tested year 2026-2029 -- same
+  structural block as St. Frances of Rome (March) and (partly) Marian
+  Saturday collisions elsewhere, she can never win her own day outright.
+
+**All 109 sanctoral entries with a `propers` id: done.** 3 left honestly
+`missing` across the whole pull (Hilary was relocated, not left missing;
+the true missing ones are St. Frances of Rome, St. Bibiana, and Ss.
+Urban I/Eleutherius/John I do have content -- they just needed a very
+late test year). Every pre-existing antiphon file that predated this
+pass has now been checked against a live Monastic query; most needed
+correction (confirmed Roman-rite sourced), a handful already matched.
 - **~52 temporal entries: not started.**
 - **94 `propers: null` saints: not started** — need a collect authored (a
   bigger, separate task) before an antiphon id even has anywhere to attach.