feat(db): add rent_payment_destinations column and multi-schema support

- Add migration 0020 for rent_payment_destinations jsonb column
- Add DB_SCHEMA env var support for multi-schema deployments
- Create custom migrate.ts script with proper search_path handling
- Update drizzle.config.ts and client.ts to use DB_SCHEMA
- Add db_schema variable to Terraform with dev=test/prod=public defaults
- Update CD workflow to set DB_SCHEMA based on branch

packages/db/drizzle/0020_natural_mauler.sql

@@ -0,0 +1 @@
+ALTER TABLE "household_billing_settings" ADD COLUMN "rent_payment_destinations" jsonb;