Give post-pentecost-15's homily reading its own Duo Séraphim responsory

Every other post-Pentecost week's own file already attaches "Duo
Séraphim" (the closing responsory before Te Deum) to the hour's *last*
reading, overriding the usual "first one, when several collapse"
convention for exactly this responsory. post-pentecost-15 was the only
week not following that pattern -- its last (homily) reading kept
Lectio 10's own responsory instead. Swapped it in, matching the other
23 weeks; removes the now-resolved "needs an hour-level responsory
slot" note from TODO.md, which was chasing a problem that didn't
actually exist.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Je2mXNHoXmi1DS3xEL67rH

TODO.md

@@ -28,14 +28,6 @@ across every hour and content type in this app.
      needs bilingual voice selection (La/En) worked out, and quality for Latin pronunciation
      is an open question. Open, not started — needs its own design pass before content/UI work
      begins.
-   - The Matins schema carries at most one responsory per reading, which can't represent a
-     responsory belonging to the *hour* rather than any single reading — concretely, the
-     closing "Duo Séraphim" (sung after the last lesson, before Te Deum) is already authored
-     as a regular reading's own responsory in 23 of 24 post-Pentecost weeks (see
-     `data/propers/nocturn-readings/post-pentecost-*.yml`), but `post-pentecost-15` alone can't
-     attach it anywhere: none of that week's 3 readings is the one it historically closes.
-     Needs a real "hour-level closing responsory" slot, not just one more reading-shaped
-     workaround.
    - Paschaltide should substitute the ordinary suffrages/ferial-Preces set with a single
      alleluia-form "Suffragium Paschale" — not modeled; the ordinary set is shown unchanged
      throughout Paschaltide instead.

src/data/propers/nocturn-readings/post-pentecost-15.yml

@@ -32,13 +32,11 @@
 # here per resulting reading: Nocturn 2's reading uses Lectio 5's
 # responsory; the Gospel reading uses Lectio 9's (the only one that's
 # genuinely its own, since Lectio 9 itself split across both new
-# readings); the homily reading uses Lectio 10's (the first responsory
-# that's unambiguously the homily's own). Known simplification, flagged
-# not fixed: Lectio 12's own closing "Duo Seraphim" responsory (with its
-# own Gloria Patri, sung specially before the Te Deum) isn't represented
-# here at all — this schema only carries one responsory per reading, and
-# that grand closing responsory doesn't belong to any single one of these
-# readings the way the others do.
+# readings). The last reading (the homily, recombined from Lectio 10-12)
+# uses Lectio 12's own closing "Duo Séraphim" instead of Lectio 10's —
+# same convention every other post-Pentecost week's own file already
+# uses (see e.g. post-pentecost-01.yml): Duo Séraphim always belongs to
+# the hour's *last* reading, not "the first one, when several collapse."
 id: post-pentecost-15
 readings:
   - nocturn: 2
@@ -197,6 +195,6 @@ readings:
         marvelled at the deeds, and grasped what they meant. Such ought we to be in the school of
         Christ.
     responsory:
-      la: "R. Numquid supplántat judícium? aut Omnípotens subvértit quod iustum est? † Líbera me, Dómine, et pone me juxta te: * Et cujúsvis manus pugnet contra me.\nV. Apprehénde arma et scutum, et exsúrge in adjutórium mihi.\nR. Et cujúsvis manus pugnet contra me."
-      en: "R. Does God pervert judgment, or does the Almighty overthrow that which is just? Deliver me, O Lord, and set me beside you, * And let any man's hand fight against me.\nV. Take hold of arms and shield: and rise up to help me.\nR. And let any man's hand fight against me."
+      la: "R. Duo Séraphim clamábant alter ad álterum: * Sanctus, sanctus, sanctus Dóminus Deus Sábaoth: * Plena est omnis terra glória ejus.\nV. Tres sunt qui testimónium dant in cælo: Pater, Verbum, et Spíritus Sanctus: et hi tres unum sunt.\nR. Plena est omnis terra glória ejus."
+      en: "R. One Seraph cried unto another: * Holy, Holy, Holy is the Lord God of hosts; * The whole earth is full of His glory.\nV. There are Three That bear record in heaven: the Father, the Word, and the Holy Ghost, and these Three are One.\nR. The whole earth is full of His glory."
     status: { la: verified, en: verified }