feat(of): seasonal weekday ferials from catholic-resources.org + date-based late Advent

Re-sources the proper weekdays of Advent (weeks 1-3), Lent, and Eastertide from
catholic-resources.org (scripts/genlect-of-season-ferials-cr.py; single-cycle, so
both -I/-II keys get the same readings). The diff caught real niedziela defects:
- Easter weekday first readings contaminated (easter-3-mon had 1 Cor 15 instead
  of Acts 6:8-15; easter-4-thu had Rev 12 instead of Acts 13:13-25).
- The Easter octave weekdays (Easter Mon-Sat) had no readings at all.
- Stray psalm-numbering artifacts (147A(146), Ps42(41)) cleared.

Late Advent (Dec 17-24) is proper to the DATE, not the Advent week, so temporal.go
now keys those days 'advent-dec-<day>' (fixing the same by-date/by-week collision
as the OT numbering) and the generator supplies them (Dec 17 = the genealogy
Matt 1:1-17; Dec 24 = the Benedictus).

157 seasonal ferial-days render across 2026-2028 with 1 residual gap
(christmas-octave-fri). Adds TestOFSeasonalFerials, credits the source, bumps to
0.43.0. Christmas-season weekdays (Dec 29-31, Jan 2-5) remain niedziela-sourced
(CR's shifted layout + Epiphany-dependent assignment -- a documented follow-up).

1 files changed, 22 insertions, 0 deletions

diff --git a/internal/caldata/of_test.go b/internal/caldata/of_test.go
index 91c9b59..086883a 100644
--- a/internal/caldata/of_test.go
+++ b/internal/caldata/of_test.go
@@ -85,3 +85,25 @@ func TestOFSundayCompleteReadings(t *testing.T) {
 		}
 	}
 }
+
+func TestOFSeasonalFerials(t *testing.T) {
+	// Seasonal weekday ferials re-sourced from catholic-resources.org: an Easter
+	// weekday no longer contaminated, the Easter octave (was missing), and the
+	// date-based late-Advent days (Dec 17-24, keyed by date not by Advent week).
+	for _, tc := range []struct{ key, firstHas string }{
+		{"easter-3-mon-I", "Acts 6:8-15"},    // had 1 Cor 15 (contamination)
+		{"easter-octave-mon-I", "Acts 2:14"}, // was absent
+		{"advent-dec-17-I", "Genesis 49"},
+		{"advent-dec-24-I", "2 Samuel 7"},
+	} {
+		var first string
+		for _, r := range TemporalReadings("new", tc.key) {
+			if r.Part == "first" {
+				first = r.Citation
+			}
+		}
+		if !strings.Contains(first, tc.firstHas) {
+			t.Errorf("%s: first = %q, want containing %q", tc.key, first, tc.firstHas)
+		}
+	}
+}