calendar: pull July's sanctoral calendar (pre-1955 pull, 7/12)

23 saints for July (18 real + 5 stubs). Caught and corrected a real
mistake in this pull's own methodology: an earlier live-query pass
recorded St. Apollinaris under July 24 based on a year where he'd
actually transferred there (his true date, the 23rd, was a Sunday that
year) — cross-checking against the raw calendar text file
(1570.txt) caught it before it went in. His real date is the 23rd, with
St. Liborius as his (permanently unwinnable) secondary; July 24 is
instead the Vigil of St. James with St. Christina as its own secondary.

Five stubs this month are all genuinely unwinnable (fixed-date
competitors) — the most of any month so far.

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

src/data/calendar/saints/st-john-gualbert.yml

@@ -0,0 +1,10 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2028-07-12 and again 2029-07-12, confirming this is a fixed
+# same-day precedence, not year-dependent) -- winner outright, Duplex,
+# over Ss. Nabor and Felix (see ss-nabor-and-felix.yml). No unique
+# Oratio/Antiphon in the source -- Common of an Abbot only.
+id: st-john-gualbert
+name: "St. John Gualbert, Abbot"
+rank: duplex
+common: common-of-an-abbot
+propers: null