propers: add December's collect and antiphon text

10 collects, 5 antiphons -- including backfilling the pre-existing
Immaculate Conception entry. St. Damasus's collect is Latin-only (no
English translation exists in the reference source at all); a few
others (All Saints, Bibiana, Immaculate Conception) needed their English
read directly from the raw source file after the live query's English
side either omitted the Oratio translation or rendered the wrong Marian
feast's text -- caught by cross-checking, not assumed.

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

src/data/propers/common/immaculate-conception-collect.yml

@@ -0,0 +1,25 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617) — Latin
+# read from the live prayTertia query's own real-date output (2025-12-08);
+# its English side rendered a *different* Marian feast's text by mistake
+# (same class of query glitch as All Saints/St. Damasus this pull, just
+# silent instead of empty, and caught only by cross-checking against the
+# raw source file directly), so the English was read from
+# web/www/horas/English/Sancti/12-08.txt instead. Its own closing formula
+# ("$Per eumdem", not the standard "$Per Dominum") is expanded to this
+# project's standard closing form for consistency, same convention used
+# throughout.
+id: immaculate-conception-collect
+text:
+  la: |
+    Orémus.
+    Deus, qui per immaculátam Vírginis Conceptiónem dignum Fílio tuo habitáculum præparásti: quǽsumus; ut qui ex morte ejúsdem Fílii tui prævísa, eam ab omni labe præservásti, nos quoque mundos ejus intercessióne ad te perveníre concédas.
+    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, by the Immaculate Conception of the Virgin, thou prepared a worthy habitation for thy Son; we beseech thee, that, as by the foreseen death of thy same Son thou preserved her from all stain of sin, so thou would grant us also, through her intercession, to come to thee with pure hearts.
+    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