Wire seasonal hymn-doxology into every plain-default Vespers hymn

Sunday's hymn ("Lucis Creator") is the one case whose Monastic source text
carries a real "*" seasonal-substitution marker (live-checked); every other
key (Mon-Sat, Advent, Lent, Passiontide, Paschaltide) is wired the same way
anyway as a deliberate broadening beyond the source, at the user's request
("the doxology is a neat way to stay tuned in to the season... we're doing a
remix, not a copy"). Each hymn's own natural ending is split into a matching
per-annum companion file, so a season/feast with no override reproduces the
original text exactly; only Nat/Epi/Pasch/Asc/Pent/Corp/Heart and the two
feast/date overrides from the previous commit actually change anything.

Real visible effect: hymns shown during Christmastide/Epiphanytide/Corpus
Christi/Sacred Heart (none of which get a distinct seasonal hymn, so these
were always the plain weekday defaults) now pick up the right doxology
instead of a generic ending; Ascensiontide and the Pentecost octave now
diverge from the rest of Paschaltide's doxology mid-season.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AGjUyhUZJaSjiniEmnLdak

src/data/propers/common/vespers-hymn-monday.yml

@@ -25,12 +25,6 @@ text:
     Sic lúminis jubar ferat:
     Ut vana cuncta próterat:
     Hanc falsa nulla cómprimant.
-
-    Præsta, Pater piíssime,
-    Patríque compar Únice,
-    Cum Spíritu Paráclito
-    Regnans per omne sǽculum.
-    Amen.
   en: |
     O great Creator of the sky,
     Who wouldest not the floods on high
@@ -51,12 +45,6 @@ text:
     So shall its rays direct us right:
     And let this faith each error chase,
     And never give to falsehood place.
-
-    Grant this, O Father, ever One
-    With Christ, thy sole-begotten Son,
-    And Holy Ghost, whom all adore,
-    Reigning and blest forevermore.
-    Amen.
 status:
   la: draft
   en: draft