feat(rsvp): sync reading position to cloud via book_configs (#3801)

docker/volumes/db/init/schema.sql

@@ -37,6 +37,7 @@ CREATE TABLE public.book_configs (
   location text NULL,
   xpointer text NULL,
   progress jsonb NULL,
+  rsvp_position text NULL,
   search_config jsonb NULL,
   view_settings jsonb NULL,
   created_at timestamp with time zone NULL DEFAULT now(),

docker/volumes/db/migrations/001_add_rsvp_position.sql

@@ -0,0 +1,4 @@
+-- Migration 001: Add rsvp_position column to book_configs
+
+ALTER TABLE public.book_configs
+  ADD COLUMN IF NOT EXISTS rsvp_position text NULL;