Fix Multi-line InitSQL Support for AWS RDS Postgres

[universe-ops]

Fixed a critical issue where multi-line initSQL configurations would fail due to shell command-line parsing limitations.

Problem

Multi-line SQL initialization commands were passed using psql -c "$INIT_SQL", which caused issues with:

• Shell variable expansion breaking on newlines
• Command-line parsing errors with complex SQL
• Quote escaping issues in shell context

Solution

Changed SQL execution method from command-line flag to stdin piping:

Before:

PGDATABASE="$DB_NAME" psql -c "$INIT_SQL"