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/sext-hymn.yml

@@ -0,0 +1,41 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617). Fixed
+# hymn for Sext, 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: sext-hymn
+text:
+  la: |
+    Rector potens, verax Deus,
+    Qui témperas rerum vices,
+    Splendóre mane ínstruis,
+    Et ígnibus merídiem:
+
+    Exstíngue flammas lítium,
+    Aufer calórem nóxium,
+    Confer salútem córporum,
+    Verámque pacem córdium.
+
+    Præsta, Pater piíssime,
+    Patríque compar Únice,
+    Cum Spíritu Paráclito
+    Regnans per omne sǽculum.
+    Amen.
+  en: |
+    O God of truth, O Lord of might,
+    Who orderest time and change aright,
+    Who send'st the early morning ray,
+    And light'st the glow of perfect day:
+
+    Extinguish thou each sinful fire,
+    And banish every ill desire;
+    And while thou keep'st the body whole,
+    Shed forth thy peace upon the soul.
+
+    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