fix(ef): two I-class feasts can no longer transfer onto the same day

RG 97/98 require a year's impeded I-class transfers to be resolved together.
transferIfImpededEF resolved each one independently, so when an early Easter
impedes both St Joseph (19 March) and the Annunciation (25 March), both walked
to the Monday after Low Sunday -- and St Joseph, losing pickEF there, was
observed on NO day of 2008, 2035 or 2046 at all. He appeared only as a
commemoration in the Annunciation's tail.

RG 96(a) settles it outright, and it is not a tie-break: the Annunciation
transferred after Easter has a sedes propria -- "quando est transferendum post
Pascha, transfertur, tamquam in sedem propriam, in feriam II post dominicam in
albis". It claims the Monday by law; the rest queue in RG 98's order (table
position, then the office impeded first) and walk around it.

New efTransferPlan resolves the whole year's transfers as a set and hands each
feast its target; transferIfImpededEF keeps the single-candidate walk and All
Souls. The stale doc comment recording this as a known unfixable limitation is
replaced -- its reasoning argued RG 97/98 tie-breaks, when RG 96(a) decides the
only collision the universal calendar actually produces.

  2008-04-01, 2035-04-03, 2046-04-03  ef-easter-2-tuesday -> St Joseph

Matches colitur on all three. Mutation-tested: bypassing the plan reddens the
new test on all three years.

fix(ef): 13 January's Baptism is omitted when Holy Family falls on it

The Holy Family Mass propers, verbatim in both photographic scans of the 1962
Missal:

  "Si festum S. Familiae occurrerit die 13 ianuarii, Missa dicitur de festo
   S. Familiae, sine commemoratione Baptismatis D.N.I.C., et sine
   commemoratione dominicae."

Sine commemoratione: the Baptism is omitted outright, not merely outranked, so
the candidate is dropped rather than left in Others. Structurally the same
answer RG 91 entry 14 gives (Festa Domini II classis: primum mobilia, deinde
fixa), but the propers' rubric is the direct authority for the omission.

lectio kept the Baptism as the observed office on all seven such years in
2005-2050 -- 2008, 2013, 2019, 2030, 2036, 2041, 2047 -- and never observed the
Holy Family Mass on 13 January at all. It already had the Holy Family Mass on
every other Sunday after Epiphany, so this was the one date it could not reach.

13 rows of the 16801-day differential fixture change; colitur agrees with all
of them.

1 files changed, 58 insertions, 0 deletions

diff --git a/internal/calendar/precedence_ef_repro_test.go b/internal/calendar/precedence_ef_repro_test.go
index 11fd6ca..1408c7c 100644
--- a/internal/calendar/precedence_ef_repro_test.go
+++ b/internal/calendar/precedence_ef_repro_test.go
@@ -11,6 +11,7 @@ package calendar_test
 // covered separately, package-internal, in precedence_ef_test.go).
 
 import (
+	"strings"
 	"testing"
 	"time"
 
@@ -158,3 +159,60 @@ func TestPurificationBeatsFebruarySunday(t *testing.T) {
 		}
 	}
 }
+
+// TestEFTwoTransfersDoNotCollide: RG 97/98 -- when an early Easter impedes BOTH
+// St Joseph (19 March) and the Annunciation (25 March), each must land on a day
+// of its own. Resolving the two walks independently sent both to the Monday
+// after Low Sunday, where St Joseph lost pickEF and was observed on NO day of
+// 2008, 2035 or 2046 at all.
+//
+// RG 96(a) fixes the Annunciation's target outright -- "quando est transferendum
+// post Pascha, transfertur, tamquam in sedem propriam, in feriam II post
+// dominicam in albis" -- so it is not a tie-break: the Annunciation takes the
+// Monday by law and St Joseph walks to the Tuesday.
+func TestEFTwoTransfersDoNotCollide(t *testing.T) {
+	for _, c := range []struct{ annunciation, joseph string }{
+		{"2008-03-31", "2008-04-01"},
+		{"2035-04-02", "2035-04-03"},
+		{"2046-04-02", "2046-04-03"},
+	} {
+		for _, w := range []struct{ date, want string }{
+			{c.annunciation, "annunciation-of-the-blessed-virgin-mary"},
+			{c.joseph, "joseph-spouse-of-the-bl-virgin-mary"},
+		} {
+			got := efCompute(w.date).Observed.Slug
+			if got != w.want {
+				t.Errorf("%s observed = %q, want %q", w.date, got, w.want)
+			}
+		}
+	}
+}
+
+// TestEFBaptismOmittedOnHolyFamilySunday: the Holy Family Mass propers, verbatim
+// in both photographic scans of the 1962 Missal -- "Si festum S. Familiae
+// occurrerit die 13 ianuarii, Missa dicitur de festo S. Familiae, sine
+// commemoratione Baptismatis D.N.I.C., et sine commemoratione dominicae."
+//
+// So on a 13 January that is itself the Sunday after Epiphany the day is the
+// Holy Family (Col 3:12-17 / Luke 2:42-52) and the Baptism is omitted OUTRIGHT,
+// not commemorated -- Others must be empty of it. lectio previously kept the
+// Baptism as the observed office on both such years in 2005-2050.
+func TestEFBaptismOmittedOnHolyFamilySunday(t *testing.T) {
+	for _, y := range []string{"2008", "2013", "2019", "2030", "2036", "2041", "2047"} {
+		d := efCompute(y + "-01-13")
+		if d.Observed.Slug != "ef-time-after-epiphany-sunday-1" {
+			t.Errorf("%s-01-13 observed = %q, want ef-time-after-epiphany-sunday-1 (Holy Family)", y, d.Observed.Slug)
+		}
+		for _, o := range d.Others {
+			if strings.Contains(o.Slug, "baptism") {
+				t.Errorf("%s-01-13 commemorates %q; the rubric says sine commemoratione Baptismatis", y, o.Slug)
+			}
+		}
+	}
+	// A 13 January that is NOT the Sunday after Epiphany keeps the Baptism.
+	for _, y := range []string{"2026", "2035"} {
+		if got := efCompute(y + "-01-13").Observed.Slug; got != "commemoration-of-the-baptism-of-the-lord" {
+			t.Errorf("%s-01-13 observed = %q, want commemoration-of-the-baptism-of-the-lord", y, got)
+		}
+	}
+}