Model Trinity Sunday as a real feast, not just a cosmetic label

Trinity Sunday wasn't modeled at all: getDayLabel had a purely
cosmetic "Trinity Sunday" label overlay for the Sunday after
Pentecost, but resolveTemporalId just fell back to post-pentecost-01
(ordinary-sunday category), so any Duplex+ saint assigned that date
(e.g. the Queenship of the BVM, fixed May 31) won outright, real
Trinity Sunday content never appearing anywhere.

Added a real temporal-feasts/trinity-sunday.yml record (Easter+56,
Duplex II. classis, live-verified). Per direct instruction,
unconditional: true (same shape as christ-the-king.yml) -- a
principal Sunday shouldn't lose a same-rank fixed-date collision, and
the one real collision case (Queenship of the BVM) isn't
independently verifiable against Monastic 1617 at all (that calendar
doesn't carry the Queenship feast -- May 31 there is St. Petronilla
instead).

Authored the full office and registered trinity-sunday in
ALWAYS_OVERRIDE_TEMPORAL_IDS -- the same generic mechanism already
built for the Pentecost-cluster fix, no new code needed: collect,
Benedictus/Magnificat antiphons, Matins hymn ("Summæ Deus cleméntiæ"),
Lauds/Vespers chapter (shared, Rom 11:33) and hymn (shared, "O lux
beáta Trínitas", already the pre-Urban VIII text), each hour's own
distinct responsory/versicle -- all live-verified 2026-05-31.

Fixed 3 pre-existing tests written around the old cosmetic-label
behavior, two of which had never-verified guesses baked in as if
correct: day-label.test.ts's "names the anchor day itself" test and
its "outranks an active octave" test (was asserting "Duplex I Class",
a guess -- the real live-verified rank is Duplex II);
transfer.test.ts's St. Felix I test.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AGjUyhUZJaSjiniEmnLdak

src/data/propers/common/lauds-hymn-trinity-sunday.yml

@@ -0,0 +1,65 @@
+# Trinity Sunday's own Lauds hymn ("O lux beáta Trínitas") — identical
+# text to Vespers' own (vespers-hymn-trinity-sunday.yml). Already the
+# pre-Urban VIII text (this project's own standing preference — see
+# CLAUDE.md) as the reference source's own default, not a separate
+# choice made here. Live-verified against Divinum Officium (Monastic
+# Tridentinum 1617), Lauds live query, 2026-05-31 (Trinity Sunday
+# itself). Self-contained — its own final stanza is a fixed, unique
+# doxology, not the shared weekday one.
+id: lauds-hymn-trinity-sunday
+text:
+  la: >-
+    O lux beáta Trínitas,
+
+    Et principális Únitas,
+
+    Jam sol recédit ígneus,
+
+    Infúnde lumen córdibus.
+
+
+    Te mane laudum cármine,
+
+    Te deprecémur véspere:
+
+    Te nostra supplex glória
+
+    Per cuncta laudet sǽcula.
+
+
+    Deo Patri sit glória,
+
+    Ejúsque soli Fílio,
+
+    Cum Spíritu Paráclito,
+
+    Et nunc, et in perpétuum. Amen.
+  en: >-
+    O Trinity of blessed Light,
+
+    O Unity of sovereign might,
+
+    as now the fiery sun departs,
+
+    shed Thou Thy beams within our hearts.
+
+
+    To Thee our morning song of praise,
+
+    to Thee our evening prayer we raise;
+
+    Thee may our glory evermore
+
+    in lowly reverence adore.
+
+
+    All laud to God the Father be;
+
+    all praise, Eternal Son, to Thee;
+
+    all glory, as is ever meet,
+
+    to God the Holy Paraclete. Amen.
+status:
+  la: verified
+  en: verified