feat: complete OF+EF calendar coverage (movable feasts, vigils, ember days, transfers)

Ordinary Form:
- Add the movable Marian memorials that have no fixed date: Mary, Mother of the
  Church (Monday after Pentecost) and the Immaculate Heart (Saturday after the
  Sacred Heart), computed in computeOF.
- General Norms 60: two coinciding obligatory memorials both become optional and
  the ferial is observed -- except Mary, Mother of the Church, which keeps
  precedence per its 2018 decree.

Extraordinary Form:
- Capture fixed-date vigils in the sanctoral harvest (Christmas, the Nativity of
  St John the Baptist, Sts Peter & Paul, St Lawrence, the Assumption, All Saints,
  the Immaculate Conception) -- previously filtered out.
- temporalEF: the movable vigils of the Ascension (I class eve) and Pentecost
  (Whitsun Eve), and the September/Advent Ember days (II class violet ferias).
- transferIfImpededEF: the Annunciation transfers past Holy Week/the Easter
  octave to the Monday after Low Sunday; All Souls moves to Nov 3 when Nov 2 is a
  Sunday.
- genlect harvests proper Masses for the new Ember/vigil days.

Adds TestEFCoverage + TestOFMovableMemorials. Bumps to 0.39.0.

Verified per-day: OF 0 real errors vs calapi (2026-2028, 100% correct-observed);
EF 0 real errors vs missalemeum (2025-2027), residual = deep-tail vigil-occurrence
and St Joseph Passiontide-transfer edges (~1-2 days/yr, documented).

1 files changed, 61 insertions, 1 deletions

diff --git a/internal/calendar/calendar.go b/internal/calendar/calendar.go
index e0f5217..99a24b3 100644
--- a/internal/calendar/calendar.go
+++ b/internal/calendar/calendar.go
@@ -29,7 +29,8 @@ func computeEF(date time.Time, sel Selection, layers []Layer) LiturgicalDay {
 		if !ok {
 			continue
 		}
-		if sameDay(when, date) {
+		effective := transferIfImpededEF(cel, when)
+		if sameDay(effective, date) {
 			cands = append(cands, candidate{Cel: cel, Temporal: false, Season: td.Season})
 		}
 	}
@@ -75,6 +76,13 @@ func computeOF(date time.Time, sel Selection, layers []Layer) LiturgicalDay {
 			cands = append(cands, candidate{Cel: cel, Temporal: false, Season: td.Season})
 		}
 	}
+	// Movable Marian memorials that have no fixed date (so they cannot live in the
+	// sanctoral file): Mary, Mother of the Church, and the Immaculate Heart.
+	for _, mm := range movableMemorialsOF(date.Year()) {
+		if sameDay(mm.when, date) {
+			cands = append(cands, candidate{Cel: mm.cel, Temporal: false, Season: td.Season})
+		}
+	}
 
 	obs, others := pick(cands)
 	day := LiturgicalDay{
@@ -104,6 +112,31 @@ func celebrationDate(cel Celebration, year int, sel Selection) (time.Time, bool)
 	return resolveDate(cel.Date, year, Easter(year))
 }
 
+// movableCel is a celebration whose date is computed (relative to Easter), not
+// read from a fixed-date layer.
+type movableCel struct {
+	when time.Time
+	cel  Celebration
+}
+
+// movableMemorialsOF returns the Ordinary Form's two movable Marian memorials,
+// which have no fixed calendar date: Mary, Mother of the Church (the Monday after
+// Pentecost) and the Immaculate Heart of Mary (the Saturday after the Sacred
+// Heart, i.e. easter+69).
+func movableMemorialsOF(y int) []movableCel {
+	e := Easter(y)
+	mk := func(off int, slug, en, pl string) movableCel {
+		return movableCel{when: e.AddDate(0, 0, off), cel: Celebration{
+			Slug: slug, Rank: RankMemorial, Class: ClassBVM, Colour: White, Layer: "universal",
+			Name: map[string]string{"en": en, "pl": pl},
+		}}
+	}
+	return []movableCel{
+		mk(50, "mary-mother-of-the-church", "Mary, Mother of the Church", "Najświętszej Maryi Panny, Matki Kościoła"),
+		mk(69, "the-immaculate-heart-of-the-blessed-virgin-mary", "The Immaculate Heart of the Blessed Virgin Mary", "Niepokalanego Serca Najświętszej Maryi Panny"),
+	}
+}
+
 // transferIfImpeded moves a solemnity off a band-1/2 temporal day to the next
 // free day. Non-solemnities are never transferred (they yield instead).
 func transferIfImpeded(cel Celebration, when time.Time, sel Selection) time.Time {
@@ -126,6 +159,33 @@ func transferIfImpeded(cel Celebration, when time.Time, sel Selection) time.Time
 	return day
 }
 
+// transferIfImpededEF moves an EF sanctoral feast off a date it cannot be kept
+// on. Two rules cover the 1962 cases: All Souls, when Nov 2 is a Sunday, is
+// transferred to the Monday (Nov 3); and a I class feast impeded by a I class
+// temporal day (Holy Week, the Easter octave) is pushed forward to the next free
+// day — for the Annunciation in Holy Week this lands on the Monday after Low
+// Sunday, past the whole privileged octave. Lower-rank feasts are only
+// commemorated, never transferred.
+func transferIfImpededEF(cel Celebration, when time.Time) time.Time {
+	if when.Month() == time.November && when.Day() == 2 && when.Weekday() == time.Sunday &&
+		strings.Contains(cel.Slug, "all-souls") {
+		return when.AddDate(0, 0, 1)
+	}
+	if cel.Rank != RankClass1 {
+		return when
+	}
+	day := when
+	for i := 0; i < 30; i++ {
+		b := temporalEF(day)
+		if precedenceEF(candidate{Cel: b.Cel, Temporal: true, Season: b.Season}) <= 2 {
+			day = day.AddDate(0, 0, 1) // impeded by a I class temporal day; push forward
+			continue
+		}
+		return day
+	}
+	return day
+}
+
 // buildCelebration types a RawCelebration.
 func buildCelebration(slug string, rc RawCelebration) Celebration {
 	c := Celebration{Slug: strings.TrimSpace(slug), Name: map[string]string{}, Layer: rc.Fields["layer"]}