Add Our Lady of the Snows (Aug 5) to the calendar

Previously excluded entirely under a stale "fixed BVM feasts aren't
modeled" note -- wrong: this app already models three other fixed BVM
feasts (assumption, immaculate-conception, nativity-bvm), and this one
has real, complete content too. Sancti/08-05.txt's untagged rank block
gives her Duplex Majus with real Nocturn 2/3 content (the
miraculous-snowfall founding legend of St. Mary Major); SanctiM/08-05.txt
confirms she's on the Monastic 1617 track too, reslicing the same
Lectio4-6.

Unlike the other three BVM feasts, she has no proper collect or
Benedictus antiphon of her own (her Rule says "ex C11" -- Common of
Feasts of the BVM) -- collect-c11.yml and
benedictus-antiphon-common-of-the-bvm.yml are real, reusable Common
templates, wired via collectCommon/benedictusCommon like any other
Common-only saint, not a private per-saint duplicate.

Live-checked via direct resolution: she wins outright on 2026-08-05 and
2027-08-05, with antiphon, collect, and Matins reading all resolving
verified. npm test (365 tests) and tsc --noEmit both pass.

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

src/data/calendar/sanctoral-calendar.yml

@@ -172,12 +172,18 @@ days:
   # 11), St. Clare (Aug 12 -- notable: a genuinely major saint, not an
   # obscure one, caught by this same gap), Ss. Hippolytus and Cassian
   # (Aug 13), St. Agapitus (Aug 18), Ss. Timothy/Hippolytus/Symphorian
-  # (Aug 22). Also excluded: Our Lady of the Snows (Aug 5, fixed BVM
-  # feast, same convention as Purification/Annunciation).
+  # (Aug 22). Our Lady of the Snows (Aug 5) was also excluded here at
+  # first under the same "fixed BVM feast" reasoning -- wrong, corrected
+  # 2026-08: unlike the genuinely-unmodeled cases above, she has real,
+  # complete content (Matins readings + Common-of-the-BVM collect/
+  # antiphon) and this app already models three other fixed BVM feasts
+  # the same way (assumption, immaculate-conception, nativity-bvm) -- see
+  # our-lady-of-the-snows.yml's own header. Added below.
   "08-01": [st-peter-ad-vincula, ss-machabees]
   "08-02": [st-stephen-i]
   "08-03": [finding-of-st-stephen]
   "08-04": [st-dominic]
+  "08-05": [our-lady-of-the-snows]
   "08-07": [st-donatus]
   "08-08": [ss-cyriacus-largus-and-smaragdus]
   "08-09": [vigil-of-st-lawrence, st-romanus]