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, 16 insertions, 5 deletions

diff --git a/internal/calfeed/json.go b/internal/calfeed/json.go
index c1a50ca..1cb0b6f 100644
--- a/internal/calfeed/json.go
+++ b/internal/calfeed/json.go
@@ -1,17 +1,28 @@
 package calfeed
 
-import "encoding/json"
+import (
+	"encoding/json"
+
+	"github.com/lukaszkasprzak/lectio/internal/config"
+)
 
 const Schema = "lectio.calendar/1"
 
 // JSON renders days as the stable lectio.calendar/1 envelope.
+//
+// "source" and "license" carry the AGPL-3.0 §13 offer to consumers who only
+// ever see this endpoint and never load the HTML UI. They are envelope
+// metadata, not day data -- adding them does not change the schema version,
+// since existing consumers read "days".
 func JSON(form string, days []DayView) ([]byte, error) {
 	if days == nil {
 		days = []DayView{}
 	}
 	return json.MarshalIndent(struct {
-		Schema string    `json:"schema"`
-		Form   string    `json:"form"`
-		Days   []DayView `json:"days"`
-	}{Schema, form, days}, "", "  ")
+		Schema  string    `json:"schema"`
+		Form    string    `json:"form"`
+		Source  string    `json:"source"`
+		License string    `json:"license"`
+		Days    []DayView `json:"days"`
+	}{Schema, form, config.SourceURL, config.License, days}, "", "  ")
 }