propers: add April's collect text

Real collect text for all 8 April saints that have one — same extraction
method as prior months. One correction to St. Robert's own English
translation in the source, which left his name in Latin genitive form
("blessed Robérti") rather than translating it — fixed, flagged in the
file as a transcription artifact, not a deliberate style choice.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/calendar/april-sanctoral.test.ts

@@ -0,0 +1,52 @@
+import { describe, expect, it } from 'vitest';
+import { resolveDay } from '../../src/calendar';
+import { getDayCollect } from '../../src/hours/resolve-common';
+
+// Clean per-annum years for these dates (no Sunday collision, and clear of
+// the movable Holy Week/Easter Octave that usually overshadows several of
+// them) — see data/calendar/saints/*.yml for per-saint source detail.
+describe('April sanctoral pull (first pass)', () => {
+  it('St. Mark wins outright with a real proper collect on an ordinary date', () => {
+    const day = resolveDay('2042-04-25');
+    expect(day.winner).toEqual({
+      kind: 'sanctoral',
+      id: 'st-mark',
+      name: 'St. Mark, Evangelist',
+      rank: 'duplex-2-classis',
+    });
+    expect(getDayCollect(day).status.en).toBe('verified');
+  });
+
+  it('St. Mark is only ever commemorated, never wins, within the Easter Octave', () => {
+    const day = resolveDay('2030-04-25');
+    expect(day.winner.kind).toBe('temporal');
+    expect(day.commemorations).toEqual([
+      { kind: 'sanctoral', id: 'st-mark', name: 'St. Mark, Evangelist', rank: 'duplex-2-classis' },
+    ]);
+  });
+
+  it('St. Robert beats St. Catherine of Siena on their shared monastic-calendar date', () => {
+    const day = resolveDay('2043-04-29');
+    expect(day.winner).toEqual({ kind: 'sanctoral', id: 'st-robert', name: 'St. Robert, Abbot', rank: 'duplex' });
+    expect(day.commemorations).toEqual([
+      { kind: 'sanctoral', id: 'st-catherine-of-siena', name: 'St. Catherine of Siena, Virgin', rank: 'simplex' },
+    ]);
+  });
+
+  it('a privileged Eastertide Sunday bumps even St. Robert (plain Duplex, not Duplex majus) to transfer forward', () => {
+    // 2029: Apr 29 is a privileged Sunday in Eastertide, so Robert can't
+    // win or be commemorated there — he transfers to Monday and wins the
+    // collision against St. Peter Martyr instead.
+    const sunday = resolveDay('2029-04-29');
+    expect(sunday.winner).toEqual({ kind: 'temporal', id: 'easter-5' });
+    expect(sunday.commemorations).toEqual([
+      { kind: 'sanctoral', id: 'st-catherine-of-siena', name: 'St. Catherine of Siena, Virgin', rank: 'simplex' },
+    ]);
+
+    const monday = resolveDay('2029-04-30');
+    expect(monday.winner).toEqual({ kind: 'sanctoral', id: 'st-robert', name: 'St. Robert, Abbot', rank: 'duplex' });
+    expect(monday.commemorations).toEqual([
+      { kind: 'sanctoral', id: 'st-peter-martyr', name: 'St. Peter Martyr, Martyr', rank: 'semiduplex' },
+    ]);
+  });
+});