Function makeRestTransport

Build an EntityTransport<T> from a Supabase client + a table name.

The returned transport:

• Maps ListQuery.filter clauses to PostgREST operators (eq, gt, in, ilike, is null, etc.).
• Compiles ListQuery.search into an or= clause across searchColumns.
• Uses count: 'exact' on first page to surface total.
• Throws TerminalError on 4xx (no retry); TransientError on 5xx or network failure.
• Honours signal via .abortSignal(signal) (supabase-js >= 2.39).