Sample report

Anyone can read 3 of your tables

Fix preview

alter table public.notes enable row level security;
create policy "notes_select_own" on public.notes
  for select to authenticated using ((select auth.uid()) = user_id);

Prompt for Lovable, Cursor or Bolt.new

Turn on row level security for notes and add a select policy so a signed-in user can only read rows where user_id = auth.uid(). Don't change other tables.