wasp-app-runner: Docker containers left running after hard process.exit()

[cprecioso]

Problem

The wasp-app-runner package frequently leaves Docker containers running after the process terminates, requiring manual cleanup with docker rm -f <container-name>.

Root Cause

The codebase has multiple hard process.exit() calls throughout that prevent proper cleanup.

When process.exit() is called, the ChildProcessManager cleanup handlers may not have sufficient time to run, and importantly, Docker container cleanup is not handled at all. While containers are started with the --rm flag, this only works if the container exits gracefully.