fix(db-tool): postgres-init: always invoke main so sourcing exports vars

Previous basename guard only ran the function when invoked as the
postgres-init binary, but consumer shellHooks source the script to
inherit POSTGRESQL_HOST/PGURL/etc. Sourcing left the function defined
but never called, leaving WIPE_PGURL/PGURL unset and breaking devshell
entry in proxydoe and ruststats.

package/db-tool/postgres-init.sh

@@ -44,6 +44,4 @@ postgres_init_main() {
   return 0
 }
 
-if [ "$(basename "$0")" = 'postgres-init' ]; then
+postgres_init_main "$@"
-  postgres_init_main "$@"
-fi