Add dynamic port lifecycle smoke test

[calvin-archastro]

Summary

• add a self-bootstrapping smoke script that creates a temporary Git workspace with three dynamically allocated services
• verify graceful supervisor shutdown removes listeners and allocation metadata
• verify SIGKILL leaves recoverable metadata and services kill-ports supports dry-run, named, and default cleanup
• run the smoke test on macOS and Linux CI

Validation

• scripts/test-dynamic-service-ports
• ASTER_BIN=target/debug/aster scripts/test-dynamic-service-ports
• cargo test --locked --all-targets --all-features
• cargo fmt --all -- --check
• cargo clippy --locked --all-targets --all-features -- -D warnings
• bash -n scripts/test-dynamic-service-ports