Add reusable Matins building blocks: types, content stores, seed data

New ResolvedPart kinds (nocturn-psalmody, te-deum) and lesson fields
(nocturn, source, isGospel, responsory) in hours/types.ts. Three new
content-store modules: propers/bible-plan.ts (the user's own continuous
scripture-reading plan, replacing the historical Nocturn-1 lectionary),
propers/nocturn-readings.ts (general feast/temporal-day Nocturn 2-3
readings, extending propers/octave-readings.ts's combine-into-one-reading
pattern via a newly-exported resolvePassages), and
propers/matins-responsories.ts (a per-book responsory pool, matched
loosely rather than by exact citation).

Data: Sunday's fixed 12-psalm/3-canticle psalmody (live-verified against
the reference engine), the invitatory antiphon, ferial hymn and
capitulum, the Te Deum, a seeded Isaiah responsory, two live-transcribed
scripture chapters, and the two bible-plan rows needed for this pass'
proof content.

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

@@ -0,0 +1,17 @@
+# Live-verified (Monastic Tridentinum 1617, 2026-09-06 and 2026-12-15).
+# 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."
+  en: "O come, * let us sing unto the Lord."
+status:
+  la: verified
+  en: verified