Remove hardcoded supabase_admin password from init.sql

The Supabase postgres image sets these passwords based on POSTGRES_PASSWORD.
Hardcoding 'postgres' caused the image's migrate.sh to fail.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

deploy/init.sql

@@ -53,9 +53,8 @@ GRANT authenticated TO authenticator;
 GRANT service_role TO authenticator;
 GRANT supabase_admin TO postgres;
 
--- Set passwords (use the same as postgres password from env)
-ALTER ROLE supabase_admin WITH PASSWORD 'postgres';
-ALTER ROLE authenticator WITH PASSWORD 'postgres';
+-- Note: Passwords for supabase_admin and authenticator are set by the Supabase image
+-- based on POSTGRES_PASSWORD environment variable. Don't override them here.
 
 -- Create schemas
 CREATE SCHEMA IF NOT EXISTS auth AUTHORIZATION supabase_auth_admin;