Let me start with the database schema. First, I'll create the SQL migration script:

The script looks correct, but the realtime publication might fail if the table is already added. Let me fix the script to be more idempotent:

Also need to make the policies idempotent:

Let me try using the Supabase tool to run the query directly:

Searched Supabase tools

I'll use the supabase_apply_migration tool for DDL operations:

Loaded apply_migration

Now I can use the tool directly via the already-provided supabase_apply_migration function: