how to get to PSM contract from repl / deploy script?

[dckc]

Describe the bug

@thisispalash is working on #5822 and he asked me how his code can talk to the PSM contract. I'm struggling to find a way.

To Reproduce

Steps to reproduce the behavior:

1. check out the community-dev branch
2. agoric init; agoric start; agoric open --repl
3. try to look up the PSM and amm
4. find amm but no PSM:

command[16] E(home.agoricNames).lookup('instance', 'psm')
history[16] unresolved Promise
command[17] E(home.agoricNames).lookup('instance', 'amm')
history[17] [Object Alleged: InstanceHandle]{}

It looks like decentral-demo-config.json doesn't start the PSM.

Expected behavior

PSM contract started in an environment where @thisispalash can get at it.

Platform Environment

• what OS are you using? what version of Node.js?
• is there anything special/unusual about your platform?
• what version of the Agoric-SDK are you using? (run git describe --tags --always)

$ git describe --tags --always
agoricxnet-7-412-g3482e0d98

Additional context

community-dev branch

[dckc]

#6498 might help a lot