propers: add May's collect and antiphon text

Real collect text for all 13 May saints that have one, plus a real
antiphon for the 3 that have one of their own (Ss. Philip and James, St.
John Before the Latin Gate, the Apparition of St. Michael) — same
extraction method as prior months. Two saints (St. Peter Celestine, St.
Urban I) have an [Ant 1] in the source that turned out to just be a
cross-reference to the generic Common template, not real unique text, so
no antiphon file was authored for them.

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

src/data/propers/common/ss-philip-and-james-collect.yml

@@ -0,0 +1,18 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617) — read
+# directly from the reference engine's own real-date output (2029-05-01).
+# Same convention as data/propers/temporal/*-collect.yml.
+id: ss-philip-and-james-collect
+text:
+  la: |
+    Orémus.
+    Deus, qui nos ánnua Apostolórum tuórum Philíppi et Jacóbi solemnitáte lætíficas: præsta, quǽsumus; ut, quorum gaudémus méritis, instruámur exémplis.
+    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 dost every year gladden us by the solemn memorial of thine Apostles Philip and James, grant us grace, we beseech thee, not only to rejoice because of their worthy deeds, but also to tread in their footsteps.
+    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