Author 5 more wholly-proper feasts' own Matins invitatory antiphons

Same gap as All Saints: Finding of the Holy Cross, Exaltation of the
Holy Cross, Most Precious Blood, Transfiguration, and Visitation of the
BVM are all duplex-majus+ feasts with a fake "proper-to-*" common and no
matins-invitatory-<id>.yml of their own, so each fell through to the
plain ferial default. Sourced from each one's own Sancti/MM-DD.txt
[Invit] block (none has a Monastic override).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LGsATZvfnpQ81HQuoF5JuL

src/data/propers/common/matins-invitatory-finding-of-the-holy-cross.yml

@@ -0,0 +1,9 @@
+# Read from web/www/horas/Latin/Sancti/05-03.txt's own [Invit] (no
+# Monastic override exists) and its English counterpart.
+id: matins-invitatory-finding-of-the-holy-cross
+text:
+  la: "Christum Regem crucifíxum, * Veníte, adorémus. (Allelúja.)"
+  en: "Christ crucified is our King. * O come, let us worship Him. (Alleluia.)"
+status:
+  la: verified
+  en: verified