calendar: pull January's sanctoral calendar (pre-1955 pull, 1/12)

20 saints for January, verified per-day against Divinum Officium (Monastic
Tridentinum 1617): 13 that actually win their day outright (rank pulled
from a live per-date query, since the static 1570/M1617 calendar text
files turned out unreliable once monastic-specific overrides apply) and
7 stubs for saints that only ever get commemorated, with an explicitly
flagged, unverified simplex rank guess pending correction.

Deliberately out of scope: pure octave-continuation days (In Octava S.
Stephani, the Epiphany-octave ferias) and fixed-date feasts of the
Lord/BMV (Circumcision, Epiphany) — sanctoral only, not temporal.

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

src/data/calendar/saints/conversion-of-st-paul.yml

@@ -0,0 +1,8 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2029-01-25, no Sunday collision) -- winner outright, Duplex majus. Own
+# proper collect and antiphon.
+id: conversion-of-st-paul
+name: "The Conversion of St. Paul, Apostle"
+rank: duplex-majus
+common: common-of-an-apostle
+propers: "conversion-of-st-paul"