calendar: pull September's sanctoral calendar (pre-1955 pull, 9/12)

14 saints (12 real winners + 2 stubs), plus a propers-slug update for the
pre-existing Nativity of the BVM entry. Two monastic-calendar-specific
finds: St. Nicholas of Tolentino (Sep 10) overrides what the base
Tridentine table treats as a plain Nativity-octave continuation, and St.
Januarius (Sep 19) is a monastic-only addition absent from the base table
entirely. Also flags (not yet acted on) that the pre-existing Sep 29 St.
Michael mapping doesn't appear to hold in this pull's actual target
track -- see the sanctoral-calendar.yml comment for detail.

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

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

@@ -0,0 +1,14 @@
+# Genuinely unwinnable stub (verified 2025-09-08, 2026-09-08) -- always
+# commemorated under the Nativity of the BVM (see nativity-bvm.yml),
+# never wins outright; both are fixed, non-movable dates, so this isn't
+# an artifact of the tested year. Unlike this month's several Nativity-
+# octave secondary saints (excluded entirely -- see the sanctoral-
+# calendar.yml comment on this month's octave-gap exclusions), this one
+# IS representable: the Nativity's own day (Sep 8) is already a normal
+# mapped sanctoral entry, so the collision engine resolves it correctly
+# without needing octave support. rank/propers unverified placeholders.
+id: st-hadrian
+name: "St. Hadrian, Martyr"
+rank: simplex
+common: common-of-a-martyr
+propers: null