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-st-peter.yml

@@ -0,0 +1,14 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), Sext.
+# Extracted (2026-08) from St. Peter ad Vincula and Ss. Peter and Paul's
+# independently-authored content, confirmed identical via diff — see
+# none-antiphon-common-of-st-peter.yml's header.
+id: sext-capitulum-common-of-st-peter
+text:
+  la: "Petrus quidem servabátur in cárcere; orátio autem fiébat sine intermissióne ab Ecclésia ad Deum pro eo. R. Deo grátias. V. Constítues eos príncipes super omnem terram. R. Mémores erunt nóminis tui, Dómine."
+  en: "Peter therefore was kept in prison. But prayer was made without ceasing of the Church unto God for him. R. Thanks be to God. V. Thou shalt make them princes over all the earth. R. They shall remember thy name, O Lord."
+citation:
+  la: "Act 12:5"
+  en: "Acts 12:5"
+status:
+  la: verified
+  en: verified