calendar: pull March's sanctoral calendar (pre-1955 pull, 3/12)

7 saints for March, all winning outright on a clean per-annum date. Notably
St. Benedict himself (Mar 21, Duplex I. classis, the founder — "S. P. N."
in the source) turns out to have no unique Oratio/Antiphon at all in this
date's source file, only Common-of-an-Abbot cross-references — flagged in
his own file to check his second (July) feast when that month comes up.

Two Benedictine-oblate saints (Frances of Rome, Gregory the Great) are
marked "O. N." (Ordinis Nostri) in the source — real significance for a
monastic calendar. St. Frances also needed a new common category,
common-of-a-widow (she's neither virgin nor martyr).

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

src/data/calendar/saints/st-frances-of-rome.yml

@@ -0,0 +1,12 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2038-03-09, clear of the movable Lenten Ember Wednesday that
+# usually overshadows this date, and not a Sunday) -- winner outright,
+# Simplex. Marked "O. N." (Ordinis Nostri, "of Our Order") in the source --
+# a Benedictine oblate, real significance for a monastic calendar
+# specifically. Own proper collect, no unique antiphon of her own. A widow
+# rather than a virgin or martyr, so a new category: "common-of-a-widow".
+id: st-frances-of-rome
+name: "St. Frances of Rome, Widow"
+rank: simplex
+common: common-of-a-widow
+propers: "st-frances-of-rome"