source without set -a sets vars in current shell but does not export them.
Child processes like envsubst cannot see unexported vars, causing all
template substitutions to produce empty strings.
Fix: set -a before source, set +a after — auto-exports every assigned var.
Deploy scripts now look for templates in INFRA_DIR first, then fall back
to the bundled copies in automa. This makes automa fully self-contained:
a .env with filled values is all that is needed — no infra checkout required.
Bundle: config.json.example, privoxy.conf.example, shadowsocks-client.service,
shadowsocks-rust.service, frps.toml.example, frps.service,
frpc.toml.example, frpc.service
