Merge branch 'engine-precedence-fixes': OF/EF calendar+readings flawlessness pass

Per-day validation vs litcal (OF) and missalemeum (EF) 2005-2050, all defects
fixed and re-validated to zero: OF calendar 0 real errors forward, OF readings
0 unresolvable, EF 0 reading gaps + resumed Sundays correct.

1 files changed, 18 insertions, 0 deletions

diff --git a/internal/calfeed/ical_test.go b/internal/calfeed/ical_test.go
index fb7ee9a..215c0e3 100644
--- a/internal/calfeed/ical_test.go
+++ b/internal/calfeed/ical_test.go
@@ -4,6 +4,8 @@ import (
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/lukaszkasprzak/lectio/internal/config"
 )
 
 func TestICalEscapeInjection(t *testing.T) {
@@ -19,6 +21,22 @@ func TestICalEscapeInjection(t *testing.T) {
 	}
 }
 
+// TestICalCarriesSourceOffer pins the AGPL-3.0 §13 offer into the VCALENDAR
+// header. Someone who subscribes to /calendar.ics in their calendar app sees
+// no lectio page at all; the feed is their entire view of the program, so it
+// carries the offer. X- properties are inert to clients that ignore them.
+func TestICalCarriesSourceOffer(t *testing.T) {
+	out := string(ICal("new", nil, time.Date(2026, 7, 27, 12, 0, 0, 0, time.UTC)))
+	for _, want := range []string{
+		"X-LECTIO-SOURCE:" + icalEscape(config.SourceURL),
+		"X-LECTIO-LICENSE:" + icalEscape(config.License),
+	} {
+		if !strings.Contains(out, want) {
+			t.Errorf("missing %q in:\n%s", want, out)
+		}
+	}
+}
+
 func TestICalStructure(t *testing.T) {
 	days := []DayView{{
 		Date: "2026-01-06", Season: "time-after-epiphany", Week: 1, Colour: "white",