propers: add April's collect text

Real collect text for all 8 April saints that have one — same extraction
method as prior months. One correction to St. Robert's own English
translation in the source, which left his name in Latin genitive form
("blessed Robérti") rather than translating it — fixed, flagged in the
file as a transcription artifact, not a deliberate style choice.

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

src/data/propers/common/st-francis-of-paola-collect.yml

@@ -0,0 +1,18 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617) — read
+# directly from the reference engine's own real-date output (2042-04-14 (his true date, Apr 2, was blocked by Holy Week that year, so he transferred here)).
+# Same convention as data/propers/temporal/*-collect.yml.
+id: st-francis-of-paola-collect
+text:
+  la: |
+    Orémus.
+    Deus, humílium celsitúdo, qui beátum Francíscum Confessórem Sanctórum tuórum glória sublimásti: tríbue, quǽsumus; ut, ejus méritis et imitatióne, promíssa humílibus prǽmia felíciter consequámur.
+    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.
+    O God, Who exaltest the meek, and hast raised up thy Blessed Confessor Francis even unto the glory of thy Saints, grant unto us, we beseech thee, for his sake, so to walk after him in lowliness of heart, that in the end we may attain, as he hath, to that great reward which Thou hast promised unto all such as be so minded.
+    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