Place Liquidation Bid via CLI

[otoole-brendan]

What is the Problem Being Solved?

In the absence of a liquidation UI for Vaults launch, we will need a means for user (presumably with bots) to be able to place bids for liquidated collateral via CLI

Description of the Design

revised by @dckc

Follow established pattern for commands that format smart wallet offers and sign/send them. See also test plan below.

Security Considerations

agoric cli relies on cosmos-style agd for key / keyring management.

Scaling Considerations

none?

Test Plan

Among others, test that...

 - [x] Users can place bids with a bidding agent as specific prices
 - [x] Users can place bids with a bidding agent as discounts to oracle price
 - [ ] Users can receive the asset(s) purchased by the bidding agent
 - [x] Users can cancel bids and receive their IST back
- [ ] https://github.com/Agoric/agoric-sdk/issues/7249

To modify a bid, users can cancel and place another bid.

Testing has been a mix of manual and automated approaches.

[otoole-brendan]

#6889 serves to document how one might follow the CLI bidding process

[dckc]

I added some detail to the design, test plan.

[dckc]

modify bid feasible? required?

Having looked at this in a little detail (#7132) I don't see how to do "modify bid". @Chris-Hibbert I don't see support for it in the contract. Did I miss it? Or did you plan to add it?

@otoole-brendan can we do without modify?

I can probably combine "exit bid offer" and "place new bid" into one cli action, if that's close enough... though partial failure makes it tricky.

p.s. in a user stories doc, I see: "If ‘modify’ is challenging, sufficient to cancel and create a new one - UI could abstract this into a ‘modify’"

[Chris-Hibbert]

I don't see how to do "modify bid". @Chris-Hibbert I don't see support for it in the contract. Did I miss it? Or did you plan to add it?

I missed this requirement. I have no plans or design. The easiest approach is probably exit and place new bid.