Alpha. Minimal claims shape withPostgresClient needs on the upstream context.
Satisfied both by withSupabase's JWKS-verified ctx.jwtClaims and by the standalone withClaims middleware — withPostgresClient only reads role and serializes the whole object into request.jwt.claims.
The composable middleware surface tracks @supabase/middleware 0.x — entry shapes, context keys, and config options may change between 0.x releases.