Author the missing Vespers Magnificat antiphon for 52 temporal ids

Every temporal id had its Lauds (Benedictus) antiphon authored, but only
3 of 57 had the Vespers (Magnificat) counterpart -- a whole-calendar
gap exposed by 2026-08-29's Vespers rendering with no Magnificat
antiphon at all. Sourced from the reference engine's static Tempora/
Sancti files, same convention and per-id reference dates already
established for the Benedictus antiphons.

advent-4 and marian-saturday are the only two ids still missing one
(neither resolves from the static files alone) -- follow-up commit.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ME8QNPdEmHSbSx1r6VmDRG

src/data/propers/temporal/christmas-octave-sunday-magnificat-antiphon.yml

@@ -0,0 +1,11 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), Vespers
+# live query, 2029-12-30 -- the Sunday within the Octave of Christmas,
+# found via the reference engine's own dedicated Tempora/Nat1-0 proper
+# (same occasion as the sibling -benedictus-antiphon.yml).
+id: christmas-octave-sunday-magnificat-antiphon
+text:
+  la: "Puer Jesus * proficiébat ætáte et sapiéntia coram Deo et homínibus."
+  en: "And Jesus advanced in wisdom * and age, and grace with God and men."
+status:
+  la: verified
+  en: verified