Wire the flexa mark into every hour's psalm-antiphon pairing

Every psalm's opening antiphon (Lauds, Prime, Terce, Sext, None,
Vespers, Compline's callers, Matins) now runs through applyFlexaMark,
marking the boundary in both the displayed antiphon and the psalm's
first verse — e.g. today's Sunday Matins Nocturn 1: "Ant. The king
rejoices ‡" / "The king rejoices ‡ in thy strength, O Lord...".
Live-verified against the reference engine's own rendering for Ps 20.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UCvvgFLrhXNVFUThz6kanw

tests/hours/flexa.test.ts

@@ -0,0 +1,16 @@
+import { describe, expect, it } from 'vitest';
+import { resolveOrdo } from '../../src/hours';
+
+describe('resolveOrdo("matins", ...) flexa mark on Ps 20', () => {
+  it("marks where today's opening antiphon leaves off, in both the antiphon itself and Ps 20's first verse (Sunday Matins, Nocturn 1, 2026-08-23)", () => {
+    const ordo = resolveOrdo('matins', '2026-08-23');
+    const ps20 = ordo.parts.find((p) => p.kind === 'psalm' && p.psalmNumber === 20);
+    expect(ps20).toBeDefined();
+    if (ps20?.kind !== 'psalm') throw new Error('expected a psalm part');
+    const firstVerse = ps20.verses[0];
+    expect(firstVerse?.text.la).toContain('‡');
+    expect(firstVerse?.text.en).toContain('‡');
+    expect(ps20.antiphon?.text.la).toContain('‡');
+    expect(ps20.antiphon?.text.en).toContain('‡');
+  });
+});