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/ss-fabian-and-sebastian.yml

@@ -0,0 +1,8 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2029-01-20, no Sunday collision) -- winner outright, Duplex. One feast
+# shared by two martyrs. Own proper collect, no unique antiphon of their own.
+id: ss-fabian-and-sebastian
+name: "Ss. Fabian and Sebastian, Martyrs"
+rank: duplex
+common: common-of-several-martyrs
+propers: "ss-fabian-and-sebastian"