notifications: per user email prefs

migrations/schema.sql

@@ -35,6 +35,7 @@ CREATE TABLE IF NOT EXISTS users(
     avatar MEDIUMBLOB NOT NULL,
     backgroundImage MEDIUMBLOB,
     loginLocationsJson MEDIUMTEXT, // { locations: [{ ip, userAgent, city, country, ts }] }
+    notificationConfigJson TEXT,
 
     INDEX creationTime_index (creationTime),
     PRIMARY KEY(id));