propers: add the temporal collects store, 52 Sunday collects

New data/propers/temporal/*.yml and propers/index.ts's getTemporalProper,
mirroring the existing common-propers store. Populated with all 52
distinct Sunday collects for the full liturgical year (Advent 1-4, the
Christmas-octave Sunday, Epiphany 1-6, Septuagesima-tide, Lent 1-4 +
Passion + Palm Sunday, the 8 Paschal-time Sundays through Pentecost, and
post-Pentecost 1-24), each verified against the real Monastic Tridentinum
1617 engine.

Keyed Pentecost/offset-based ("post-pentecost-N-collect"), not
Trinity-counted — that's a display choice for calendar/day-label.ts, kept
independent of this content's storage identity. 8 of the 52 needed to be
read directly from the reference engine's source files plus its standard
closing-formula macros, since a real saint outranks those particular
Sundays on every candidate year checked and a live date query would only
ever return the saint's own collect.

src/data/propers/temporal/easter-sunday-collect.yml

@@ -0,0 +1,21 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617) -- read
+# directly from the reference engine's own real-date output (not
+# reconstructed from memory). Keyed Pentecost/offset-based
+# ("post-pentecost-N") rather than Trinity-counted deliberately: this is
+# content storage, kept scheme-agnostic, independent of whatever counting
+# convention calendar/day-label.ts shows on screen for the same Sunday.
+id: easter-sunday-collect
+text:
+  la: |
+    Orémus.
+    Deus, qui hodiérna die per Unigénitum tuum æternitátis nobis áditum devícta morte reserásti: vota nostra, quæ præveniéndo aspíras, étiam adjuvándo proséquere.
+    Per eúmdem Dóminum nostrum Jesum Christum Fílium tuum, qui tecum vivit et regnat in unitáte Spíritus Sancti, Deus, per ómnia sǽcula sæculórum.
+    R. Amen.
+  en: |
+    Let us pray.
+    God, who on this day, through thy Only-begotten Son, overcame death, and opened to us the gate of everlasting life: as by thy anticipating grace, thou breathest good desires into our hearts, so also, by thy gracious help, bring them to good effect.
+    Through the same Jesus Christ, thy Son, Our Lord, Who liveth and reigneth with thee in the unity of the Holy Ghost, God, world without end.
+    R. Amen.
+status:
+  la: verified
+  en: verified