propers: add the Terce/Sext/None hymns

Fixed, self-contained text (including each hymn's own final doxology
stanza) — unlike Prime's/Compline's hymns, these don't change by season,
so there's no appendDoxology split. Verified against Divinum Officium
(Monastic Tridentinum 1617).

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

src/data/propers/common/terce-hymn.yml

@@ -0,0 +1,41 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617). Fixed
+# hymn for Terce, invariant by season (per explicit user direction) — the
+# whole text including its own final doxology stanza is self-contained,
+# not run through hymn-doxology.ts the way Prime's/Compline's hymns are.
+id: terce-hymn
+text:
+  la: |
+    Nunc, Sancte, nobis, Spíritus,
+    Unum Patri cum Fílio,
+    Dignáre promptus íngeri
+    Nostro refúsus péctori.
+
+    Os, lingua, mens, sensus, vigor
+    Confessiónem pérsonent.
+    Flamméscat igne cáritas,
+    Accéndat ardor próximos.
+
+    Præsta, Pater piíssime,
+    Patríque compar Únice,
+    Cum Spíritu Paráclito
+    Regnans per omne sǽculum.
+    Amen.
+  en: |
+    Come Holy Ghost who ever One
+    Art with the Father and the Son,
+    It is the hour, our souls possess
+    With thy full flood of holiness.
+
+    Let flesh and heart and lips and mind
+    Sound forth our witness to mankind;
+    And love light up our mortal frame,
+    Till others catch the living flame.
+
+    Almighty Father, hear our cry,
+    Through Jesus Christ, our Lord most High,
+    Who, with the Holy Ghost and thee,
+    Doth live and reign eternally.
+    Amen.
+status:
+  la: verified
+  en: verified