* fix: Add reaper to coder agent
- The coder agent runs as PID 1 in some of our Docker workspaces.
In such cases it is the responsibility of the init process to
reap dead processes. Failing to do so can result in an inability
to create new processes by running out of PIDs.
This PR adds a reaper to our agent that is only spawned if it
detects that it is PID1.
