calendar: pull October's sanctoral calendar (pre-1955 pull, 10/12)

16 saints (14 real winners + 2 stubs). Three monastic-calendar-specific
finds this month: Ss. Placid and Companions (Oct 5, St. Benedict's own
disciple, Duplex II. classis -- absent from the base Tridentine table
entirely), St. Justina (Oct 7, reassigns what the base table gives to
St. Marcus, Pope), and St. Gall (Oct 16, founder of St. Gallen, also
absent from the base table). No octave-gap exclusions this month.

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

src/data/calendar/saints/st-justina.yml

@@ -0,0 +1,16 @@
+# A monastic-calendar-specific reassignment, not a mistake: the base
+# Tridentine table (1570.txt) has St. Marcus, Pope, as Oct 7's primary,
+# but the monastic-specific delta table (M1617.txt) overrides that day
+# with this saint instead, demoting Marcus to a commemoration (see
+# st-marcus.yml) -- confirmed live (Monastic Tridentinum 1617,
+# 2025-10-07 and 2026-10-07), winning outright at Duplex. Same class of
+# finding as April's St. Robert/St. Catherine and September's St.
+# Nicholas of Tolentino reassignments. No unique collect: the raw file at
+# this MM-DD slot (Sancti/10-07.txt) is actually Our Lady of the Rosary's
+# (a later, 1573+ feast) -- a live prayTertia query for the Monastic 1617
+# track returns no Oratio at all, confirming propers: null is correct.
+id: st-justina
+name: "St. Justina, Virgin and Martyr"
+rank: duplex
+common: common-of-a-virgin-martyr
+propers: null