Processes started via the agent process API inherited the agent's
own working directory (/tmp/coder.xxx) when no WorkDir was
specified. SSH sessions already use a fallback chain: configured
agent directory > $HOME. This wires the same manifest directory
closure into the process manager so the priority is now:
explicit req.WorkDir > agent configured dir > $HOME
The resolved directory is recorded on the process struct so
ProcessInfo.WorkDir and pathStore notifications reflect where
the process actually ran.
Mathias Fredriksson
119030d795