ready to merge and ready to discard as states

internal/store/migrations/063-add-task-ready.sql

@@ -0,0 +1,10 @@
+ALTER TABLE tasks ADD COLUMN ready TEXT NOT NULL DEFAULT '';
+UPDATE tasks SET ready = coalesce((
+	SELECT CASE e.kind WHEN 'task.ready' THEN 'merge' ELSE 'discard' END FROM events e
+	WHERE e.task_id = tasks.id AND e.kind IN ('task.ready', 'task.discard_suggested')
+	AND NOT EXISTS (
+		SELECT 1 FROM events l WHERE l.task_id = tasks.id AND l.seq > e.seq
+		AND (l.kind = 'inbox.created' OR (l.kind = 'snapshot.created' AND json_extract(l.payload, '$.trigger') != 'answer'))
+	)
+	ORDER BY e.seq DESC LIMIT 1
+), '') WHERE status = 'active';