Fix chat type persistence and board flow

etc/db/work-db/sql/board-posts.sql

@@ -2,6 +2,7 @@ create table if not exists board_posts (
   id serial primary key,
   title varchar(200) not null,
   content text not null,
+  attachments_json text not null default '[]',
   automation_plan_item_id integer null,
   automation_received_at timestamptz null,
   created_at timestamptz not null default now(),