Give the Matins invitatory antiphon a real weekday cycle

The plain ferial fallback was a single fixed year-round text that was
actually just Monday's own antiphon, mislabeled in its own comment as
live-verified for 2026-09-06 (a Sunday). The real Monastic 1617 source
genuinely varies this antiphon Sunday-Saturday, same shape as the Matins
hymn's own weekday cycle. Adds the six missing weekday variants and
dispatches on weekday in resolveMatinsInvitatoryText.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W8cttEhwbN3f6hiHQHqCae

TODO.md

@@ -11,10 +11,6 @@ content in the same shape, not a design change. The dated log below is that pipe
 ## Open work, in priority order
 
 1. **Mechanism gaps**
-   - **2026-09-06 invitatory antiphon questioned** — user flagged today's (2026-09-06)
-     invitatory antiphon as suspect; needs tracing back to its source (override > octave >
-     Common > season > ferial chain in `hours/matins.ts`'s invitatory resolution) to find
-     and fix whatever underlying bug or content problem produced it. Not yet investigated.
    - **Gospel+homily pairing shouldn't carry a responsory** — user, 2026-09-06: when a Matins
      Gospel pericope is immediately followed by its own patristic homily (the paired
      `gospel`/homily rendering — see `hours/matins.ts`'s Gospel+homily-fold-in convention),
@@ -6445,3 +6441,28 @@ Albis", i.e. Low Sunday, not yet itself named beyond a generic ordinal — a sep
 still-open gap) carries a name distinct from the plain "Die N" pattern.
 
 `npm test` (2066 passed) and `tsc --noEmit` both pass.
+
+### Matins invitatory antiphon weekday cycle — closed (2026-09-06)
+
+User flagged 2026-09-06's (a plain Sunday, `post-pentecost-15`) invitatory antiphon as suspect.
+Traced it to a real content bug, not a resolution-order bug: `matins-invitatory-antiphon.yml` (the
+final ferial fallback in `resolveMatinsInvitatoryText`) held a single fixed year-round text
+("Veníte, * Exsultémus Dómino") that its own header claimed was "live-verified... 2026-09-06" —
+that was wrong. Querying the live reference engine for that exact date returns a different text
+("Adorémus Dóminum, * Qui fecit nos"), and querying a full week showed the real source
+(`Psalterium/Special/Matutinum Special.txt`'s `[Invit Trid_]` block) genuinely varies the plain
+`{Antiphona ex Psalterio secundum tempora}` invitatory antiphon Sunday-Saturday — same shape as the
+Matins hymn's own weekday cycle (`matins-hymn-ferial-tuesday.yml` etc., closed 2026-09-04). The
+fixed text turned out to be Monday's own real antiphon, silently standing in for every other
+weekday including Sunday.
+
+Fixed the same way as the hymn cycle: six new weekday-specific files
+(`matins-invitatory-antiphon-{sunday,tuesday,wednesday,thursday,friday,saturday}.yml`, full
+Latin+English pulled from the reference engine's own `Invit Trid_`/`Invit Trid` blocks, Latin and
+English respectively), `matins-invitatory-antiphon.yml` (no day suffix) still used for Monday.
+`hours/matins.ts`'s `resolveMatinsInvitatoryText` now dispatches on `day.weekday` for its final
+fallback tier, same pattern as `resolveMatinsHymn`'s `weekdayFerialHymnIds`. Two pre-existing tests
+in `tests/hours/matins.test.ts` hardcoded "Veníte" as the generic ferial default — both dates are
+actually Tuesdays, updated to expect Tuesday's own real text ("Jubilémus Deo").
+
+`npm test` (2066 passed) and `tsc --noEmit` both pass.

src/data/propers/common/matins-invitatory-antiphon-friday.yml

@@ -0,0 +1,16 @@
+# Friday's own plain ferial Matins invitatory antiphon (Psalterium/
+# Special/Matutinum Special.txt's "Invit Trid_" block, `Feria VI=`). Its
+# English happens to be byte-identical to Sunday's own
+# (matins-invitatory-antiphon-sunday.yml) — confirmed in the source, not
+# a copy-paste slip: both weekdays' Latin renders as "Let us worship the
+# Lord, for He is our Maker" in the reference engine's own translation
+# despite slightly different Latin wording. See matins-invitatory-
+# antiphon-sunday.yml's header for the weekday-cycle mechanism this
+# belongs to; live-verified 2026-09-06.
+id: matins-invitatory-antiphon-friday
+text:
+  la: "Adorémus Dóminum, * Quóniam ipse fecit nos."
+  en: "Let us worship the Lord, for * He is our Maker."
+status:
+  la: verified
+  en: verified

src/data/propers/common/matins-invitatory-antiphon-saturday.yml

@@ -0,0 +1,14 @@
+# Saturday's own plain ferial Matins invitatory antiphon (Psalterium/
+# Special/Matutinum Special.txt's "Invit Trid_" block, `Sabbato=`).
+# Reached only when Saturday is neither Marian (see calendar/index.ts's
+# applyMarianSaturday) nor covered by a season's own seasonal invitatory
+# — same real-world rarity as matins-hymn-ferial-saturday.yml's own case.
+# See matins-invitatory-antiphon-sunday.yml's header for the weekday-cycle
+# mechanism this belongs to; live-verified 2026-09-06.
+id: matins-invitatory-antiphon-saturday
+text:
+  la: "Dóminum, Deum nostrum, * Veníte, adorémus."
+  en: "The Lord our God: * O come, let us worship Him."
+status:
+  la: verified
+  en: verified

src/data/propers/common/matins-invitatory-antiphon-sunday.yml

@@ -0,0 +1,16 @@
+# Sunday's own plain ferial Matins invitatory antiphon (Psalterium/Special/
+# Matutinum Special.txt's "Invit Trid_" block, `Dominica=`) — the plain
+# `{Antiphona ex Psalterio secundum tempora}` weekday cycle genuinely
+# varies Sunday-Saturday, same shape as the Matins hymn's own weekday
+# cycle (see matins-hymn-ferial-tuesday.yml etc.). `matins-invitatory-
+# antiphon.yml` (no day suffix) had been standing in for every day
+# including Sunday with what's actually Monday's own text — reported by
+# the user 2026-09-06 as suspect and live-verified against Monastic
+# Tridentinum 1617 directly.
+id: matins-invitatory-antiphon-sunday
+text:
+  la: "Adorémus Dóminum, * Qui fecit nos."
+  en: "Let us worship the Lord, for * He is our Maker."
+status:
+  la: verified
+  en: verified

src/data/propers/common/matins-invitatory-antiphon-thursday.yml

@@ -0,0 +1,11 @@
+# Thursday's own plain ferial Matins invitatory antiphon (Psalterium/
+# Special/Matutinum Special.txt's "Invit Trid_" block, `Feria V=`).
+# See matins-invitatory-antiphon-sunday.yml's header for the weekday-cycle
+# mechanism this belongs to; live-verified 2026-09-06.
+id: matins-invitatory-antiphon-thursday
+text:
+  la: "Dóminum, qui fecit nos, * Veníte, adorémus."
+  en: "It is the Lord That hath made us: * O come, let us worship Him."
+status:
+  la: verified
+  en: verified

src/data/propers/common/matins-invitatory-antiphon-tuesday.yml

@@ -0,0 +1,11 @@
+# Tuesday's own plain ferial Matins invitatory antiphon (Psalterium/
+# Special/Matutinum Special.txt's "Invit Trid_" block, `Feria III=`).
+# See matins-invitatory-antiphon-sunday.yml's header for the weekday-cycle
+# mechanism this belongs to; live-verified 2026-09-06.
+id: matins-invitatory-antiphon-tuesday
+text:
+  la: "Jubilémus Deo, * Salutári nostro."
+  en: "Let us make a joyful noise to * the God of our salvation."
+status:
+  la: verified
+  en: verified

src/data/propers/common/matins-invitatory-antiphon-wednesday.yml

@@ -0,0 +1,11 @@
+# Wednesday's own plain ferial Matins invitatory antiphon (Psalterium/
+# Special/Matutinum Special.txt's "Invit Trid_" block, `Feria IV=`).
+# See matins-invitatory-antiphon-sunday.yml's header for the weekday-cycle
+# mechanism this belongs to; live-verified 2026-09-06.
+id: matins-invitatory-antiphon-wednesday
+text:
+  la: "In manu tua, Dómine, * Omnes fines terræ."
+  en: "In Thy hand, O Lord, * are the inmost depths of the earth."
+status:
+  la: verified
+  en: verified

src/data/propers/common/matins-invitatory-antiphon.yml

@@ -1,13 +1,25 @@
-# Live-verified (Monastic Tridentinum 1617, 2026-09-06 and 2026-12-15).
+# This is Monday's own plain ferial Matins invitatory antiphon
+# (Psalterium/Special/Matutinum Special.txt's "Invit Trid_" block, `Feria
+# II=`). Its original comment claimed this text was "live-verified...
+# 2026-09-06" as the year-round default — wrong: that date query actually
+# returns Sunday's own distinct text ("Adorémus Dóminum, * Qui fecit
+# nos.", matins-invitatory-antiphon-sunday.yml), not this one. The real
+# `{Antiphona ex Psalterio secundum tempora}` cycle genuinely varies
+# Sunday-Saturday, same shape as the Matins hymn's own weekday cycle (see
+# matins-hymn-ferial.yml's own header) — user flagged today's rendering
+# as suspect 2026-09-06, traced to this file standing in for every
+# weekday including Sunday. `hours/matins.ts`'s
+# `resolveMatinsInvitatoryText` now looks up a weekday-specific id
+# (matins-invitatory-antiphon-sunday/-tuesday/-wednesday/-thursday/
+# -friday/-saturday) for those six days; this file (no day suffix) is
+# still used directly for Monday, same convention as matins-hymn-ferial.
+#
 # Real practice repeats this antiphon as an interspersed refrain between
 # verse groups of Psalm 94 (the historical "Venite" invitatory shape) —
 # deliberately not modeled that way here, per direct instruction: this app
 # frames it like any other psalm antiphon instead, one opening
 # (incipit-or-full, same rank rule as everywhere else) and one full
 # repeat after, via hours/matins.ts's plain 'psalm' + 'antiphon' parts.
-# Fixed year-round for now — real practice does vary this by season/feast
-# (`{Antiphona ex Psalterio secundum tempora}` in the source); not yet
-# modeled, a deferred follow-on (see TODO.md).
 id: matins-invitatory-antiphon
 text:
   la: "Veníte, * Exsultémus Dómino."

src/hours/matins.ts

@@ -345,7 +345,21 @@ function resolveMatinsInvitatoryText(day: LiturgicalDay): ResolvedText {
       return seasonal;
     }
   }
-  return resolveCommon('matins-invitatory-antiphon');
+  // The plain `{Antiphona ex Psalterio secundum tempora}` weekday cycle
+  // (Psalterium/Special/Matutinum Special.txt's "Invit Trid_" block) —
+  // same weekday-varying shape as `resolveMatinsHymn`'s own cycle, found
+  // missing the same way (user flagged 2026-09-06's Sunday rendering as
+  // suspect; it was silently reusing Monday's own text). Monday's text
+  // still lives at the unsuffixed `matins-invitatory-antiphon` id.
+  const weekdayInvitatoryIds: Partial<Record<Weekday, string>> = {
+    sunday: 'matins-invitatory-antiphon-sunday',
+    tuesday: 'matins-invitatory-antiphon-tuesday',
+    wednesday: 'matins-invitatory-antiphon-wednesday',
+    thursday: 'matins-invitatory-antiphon-thursday',
+    friday: 'matins-invitatory-antiphon-friday',
+    saturday: 'matins-invitatory-antiphon-saturday',
+  };
+  return resolveCommon(weekdayInvitatoryIds[day.weekday] ?? 'matins-invitatory-antiphon');
 }
 
 /** The Invitatory (Ps 94) — real practice interleaves its antiphon as a

tests/hours/matins.test.ts

@@ -29,7 +29,11 @@ describe('resolveOrdo("matins", ...) ferial (1-nocturn) branch', () => {
     expect(ordo.parts[3]).toMatchObject({ kind: 'section-heading', label: 'Invitatory' });
     expect(ordo.parts[4]).toMatchObject({ kind: 'psalm', psalmNumber: 94 });
     const invitatoryAntiphon = (ordo.parts[4] as { antiphon?: { text: Record<string, string> } }).antiphon;
-    expect(invitatoryAntiphon?.text.la).toContain('Veníte');
+    // FERIAL_DATE is a Tuesday — its own weekday-specific invitatory
+    // antiphon (see hours/matins.ts's resolveMatinsInvitatoryText), not
+    // Monday's "Veníte" text every weekday used to share before the
+    // weekday cycle was built (2026-09-06).
+    expect(invitatoryAntiphon?.text.la).toContain('Jubilémus Deo');
     // Real practice repeats the invitatory antiphon between verse groups —
     // deliberately not modeled that way here (see hours/matins.ts's own
     // header): confirm there's exactly one standalone repeat, not several.
@@ -1090,7 +1094,10 @@ describe('resolveOrdo("matins", ...) Common-of-an-Apostle hymn + invitatory (202
     // ferial one -- season outranks weekday in resolveMatinsHymn's own
     // precedence, same as everywhere else.
     expect(hymnLatin(FERIAL_DATE)).toContain('Verbum supérnum, pródiens');
-    expect(invitatoryFullLatin(FERIAL_DATE)).toContain('Veníte');
+    // Advent has no seasonal invitatory antiphon authored, so this falls
+    // through to Tuesday's own weekday text (see hours/matins.ts's
+    // resolveMatinsInvitatoryText and its 2026-09-06 weekday-cycle fix).
+    expect(invitatoryFullLatin(FERIAL_DATE)).toContain('Jubilémus Deo');
     expect(invitatoryFullLatin(FERIAL_DATE)).not.toContain('Regem Apostolórum');
   });
 });