propers: add September's collect and antiphon text

6 collects, 1 antiphon -- including backfilling the pre-existing Nativity
of the BVM entry now that the pulling methodology exists.

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

src/data/propers/common/ss-cyprian-and-justina-collect.yml

@@ -0,0 +1,17 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617) — read
+# directly from the reference engine's own real-date output (2025-09-26).
+id: ss-cyprian-and-justina-collect
+text:
+  la: |
+    Orémus.
+    Beatórum Mártyrum Cypriáni et Justínæ nos, Dómine, fóveant continuáta præsídia: quia non désinis propítius intuéri, quos tálibus auxíliis concésseris adjuvári.
+    Per Dóminum nostrum Jesum Christum, Fílium tuum: qui tecum vivit et regnat in unitáte Spíritus Sancti, Deus, per ómnia sǽcula sæculórum.
+    ℟. Amen.
+  en: |
+    Let us pray.
+    Lord, let the succour of thy blessed martyrs Cyprian and Justina never fail us, since Thou never ceasest to look in mercy upon any unto whom Thou dost grant the stay of such helpers.
+    Through Jesus Christ, thy Son our Lord, Who liveth and reigneth with thee, in the unity of the Holy Ghost, God, world without end.
+    ℟. Amen.
+status:
+  la: verified
+  en: verified