Wire seasonal hymn-doxology into the Matins ferial hymn

The plain ferial hymn's Monastic source (Day1-6 Hymnus,
Psalterium/Special/Matutinum Special.txt) carries a real "*" seasonal-
substitution marker, live-checked against the reference engine. Splits the
hymn's own natural doxology ending into a new per-annum companion file and
swaps it via getHymnDoxologyId/appendDoxology, same pattern already used by
Prime and Compline.

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

src/data/propers/common/matins-hymn-doxology-per-annum.yml

@@ -0,0 +1,16 @@
+# The ferial Matins hymn's own natural doxology ending, split out of
+# matins-hymn-ferial.yml so hours/matins.ts can swap it seasonally via
+# hymn-doxology.ts — the reference source's weekday (Day1-6) Matins hymns
+# each carry a real "*" substitution marker here, live-checked in
+# Psalterium/Special/Matutinum Special.txt, all sharing this same Latin
+# ending; the Sunday (Day0) form has no such marker (its own doxology,
+# "Præstet hoc nobis Déitas beáta...", is fixed) — not modeled here since
+# vu's Matins doesn't distinguish Sunday from ferial (see matins.ts).
+# Text/status carried over unchanged from the original file.
+id: matins-hymn-doxology-per-annum
+text:
+  la: "Præsta, Pater piíssime,\nPatríque compar Únice,\nCum Spíritu Paráclito\nRegnans per omne sǽculum. Amen."
+  en: "Grant this, O Father ever One\nWith Christ, thy sole-begotten Son,\nAnd Holy Ghost, whom all adore,\nReigning and blest forevermore. Amen."
+status:
+  la: verified
+  en: verified

src/data/propers/common/matins-hymn-ferial.yml

@@ -4,6 +4,11 @@
 # year-round text; only this one (evidently the ordinary-time/per-annum
 # form) is authored so far. Seasonal variants deferred (see TODO.md),
 # same incremental-content pattern as everywhere else in this project.
+#
+# The closing doxology stanza is split out into
+# matins-hymn-doxology-per-annum.yml (see hours/matins.ts) — the source
+# carries a real "*" seasonal-substitution marker there (live-checked
+# 2026-09-03, Psalterium/Special/Matutinum Special.txt).
 id: matins-hymn-ferial
 text:
   la: >-
@@ -41,15 +46,6 @@ text:
     Et ore te canéntium
 
     Laudéris in perpétuum.
-
-
-    Præsta, Pater piíssime,
-
-    Patríque compar Únice,
-
-    Cum Spíritu Paráclito
-
-    Regnans per omne sǽculum. Amen.
   en: >-
     Our limbs refreshed with slumber now,
 
@@ -85,15 +81,6 @@ text:
     That by their lips who thee adore
 
     Thou mayst be praised forevermore.
-
-
-    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: verified
   en: verified

src/hours/matins.ts

@@ -76,9 +76,11 @@ import { getPsalmVerses } from '../psalter';
 import { getPsalmsFor, type PsalmRef } from '../psalter/distribution';
 import { getScriptureVerses } from '../scripture';
 import { getOpeningVersicleId } from './opening-versicle';
+import { getHymnDoxologyId } from './hymn-doxology';
 import { applyFlexaMark } from './antiphon';
 import {
   resolveCommon,
+  appendDoxology,
   getDayCollect,
   getOfficeOverrideId,
   resolveOfficeWinner,
@@ -454,7 +456,14 @@ function resolveMatinsHymn(day: LiturgicalDay): ResolvedText {
       return seasonal;
     }
   }
-  return resolveCommon('matins-hymn-ferial');
+  // The plain ferial hymn's own Monastic source (Day1-6 Hymnus, Psalterium/
+  // Special/Matutinum Special.txt) carries a real seasonal-doxology
+  // substitution marker (live-checked 2026-09-03) — unlike the Advent/
+  // Paschaltide seasonal hymns above, whose Monastic forms are each fixed,
+  // non-swapping text, so only this final fallback needs the swap.
+  const body = resolveCommon('matins-hymn-ferial');
+  const doxology = resolveCommon(getHymnDoxologyId(day, 'matins-hymn-doxology-per-annum'));
+  return appendDoxology(body, doxology);
 }
 
 /** The plain ferial weekday nocturn's real antiphoned psalmody — a