calendar: pull June's sanctoral calendar (pre-1955 pull, 6/12)

18 saints for June, all winning outright on a clean per-annum date — no
stubs this month, including two normally blocked by the generic
"Sanctae Mariae Sabbato" Saturday votive, which just needed a
non-Saturday year instead.

Three distinct Pauline feasts now exist in this pull (Conversion of St.
Paul, Jan 25; Ss. Peter and Paul, June 29; Commemoration of St. Paul,
June 30) plus a second St. Leo (Leo II, June 28, distinct from Leo I in
April). The Nativity of St. John the Baptist (Duplex I. classis, the
highest rank pulled so far) is kept in the sanctoral store despite the
very high rank, same as the Conversion of St. Paul/Chair-of-Peter
feasts — it's about the saint himself, not a feast of the Lord/BVM.

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

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

@@ -0,0 +1,8 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2035-06-20, no Sunday collision) -- winner outright, Simplex. No
+# unique Oratio/Antiphon in the source -- Common of a Martyr Bishop only.
+id: st-silverius
+name: "St. Silverius, Pope and Martyr"
+rank: simplex
+common: common-of-a-martyr-bishop
+propers: null