Extract shared Commons for Prime/Terce/Sext/None minor-hour content

A systematic diff across all 29 duplex-majus+ saints' P/T/S/N files found
real shared-Common groups beyond the pairs noticed in passing while
authoring them. Extracted into shared data/propers/common/{hour}-antiphon-
common-of-*.yml / {hour}-capitulum-common-of-*.yml files and wired via a
new SaintRecord.minorHoursCommon field, with resolveMinorHourAntiphon/
resolveMinorHourChapter falling back to it when a saint has no proper file
of their own. Deliberately a separate field from the existing (previously
unused) `common` field: the minor hours don't always draw from the same
Common category as the saint's overall classification -- both Chair of
St. Peter feasts are `common: common-of-an-apostle` by rank, but their
P/T/S/N content is Common of a Confessor Bishop (Peter considered as
bishop of that see).

Four groups extracted (87 duplicate files collapsed to 21 shared ones),
each confirmed byte-identical via diff first: common-of-apostles (8
saints, all 4 hours), common-of-a-confessor-bishop (Chair of Peter pair
share antiphons+chapters, Martin of Tours shares only chapters), common-
of-the-bvm (Nativity BVM + Immaculate Conception's Sext/None/Terce
chapters -- the Assumption's own stay proper, different reading + proper
versicles), and common-of-st-peter (St. Peter ad Vincula + Ss. Peter and
Paul, not a real Common category, just genuinely identical Petrine
content).

Deliberately left un-extracted: St. Mark, St. John Before the Latin Gate,
and Ss. Philip and James share identical text that live-checking shows is
Paschaltide-seasonal (all three landed within the Easter octave weeks on
their queried dates, despite disagreeing `common` classifications) rather
than a fixed per-saint-category Common -- folding it into the same
mechanism would misrepresent season-contingent content as timeless. Left
as individually-authored files; flagged in TODO.md as needing a real
Paschaltide-awareness mechanism this app doesn't have yet for any hour.

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

src/data/propers/common/sext-capitulum-common-of-the-bvm.yml

@@ -0,0 +1,17 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), Sext.
+# Extracted (2026-08) from the Nativity of the BVM and the Immaculate
+# Conception's independently-authored content, confirmed byte-for-byte
+# identical via diff. The reading body (Sir 24:15-16) matches the
+# Assumption's own Sext capitulum too, but her versicle is proper to her
+# own feast ("Assúmpta est María in cælum...") rather than this Common's
+# plain one — see assumption-sext-capitulum.yml and TODO.md.
+id: sext-capitulum-common-of-the-bvm
+text:
+  la: "Et sic in Sion firmáta sum, et in civitáte sanctificáta simíliter requiévi, et in Jerúsalem potéstas mea. Et radicávi in pópulo honorificáto, et in parte Dei mei heréditas illíus, et in plenitúdine sanctórum deténtio mea. R. Deo grátias. V. Adjuvábit eam Deus vultu suo. R. Deus in médio ejus, non commovébitur."
+  en: "And so was I established in Sion, and in the holy city likewise I rested, and my power was in Jerusalem. And I took root in an honourable people, and in the portion of my God his inheritance, and my abode is in the full assembly of saints. R. Thanks be to God. V. God shall help her with His countenance. R. God is in the midst of her, she shall not be moved."
+citation:
+  la: "Sir 24:15-16"
+  en: "Sir 24:15-16"
+status:
+  la: verified
+  en: verified