idle fix

[jrhea]

idle fix

Fixes #367, #397.

A detailed explanation of the issue and fix is given in the issue, but the TL;DR is that the previous implementation of the conservation of present value dealt with excess idle funds only during removeLiquidity, which created situations in which the active LPs had control over idle funds that would ultimately go to the withdrawal pool. This PR fixes this issue by updating the logic used to pay out the withdrawal pool in closeLong and closeShort.

netting fix

In order for the idle fix to work properly, a modification was made to how we update the checkpoint exposure. the tl;dr is that we only zero out checkpoint exposure when:

• it is a long and a checkpoint boundary bc we know all the positions have been closed out. Remember, applyCloseLong() closes out shorts, then longs.
• it is a short and a checkpoint boundary and there are no longs to close out
• it is not a checkpoint boundary, but there are no more open positions

NOTE: This PR replaces #370

[coveralls]

coverage: 91.845% (-0.7%) from 92.508% when pulling d635a52 on netting-bug into bdac1aa on main.

[github-actions]

Hyperdrive Gas Benchmark

Benchmark suite	Current: d635a52	Previous: 0cb80cc	Deviation	Status
addLiquidity: min	785 gas	785 gas	0%	🟰
addLiquidity: avg	54981 gas	46879 gas	17.2828%	🚨
addLiquidity: max	99007 gas	80516 gas	22.9656%	🚨
checkpoint: min	514 gas	514 gas	0%	🟰
checkpoint: avg	29512 gas	29372 gas	0.4766%	🚨
checkpoint: max	68792 gas	82072 gas	-16.1809%	✅
closeLong: min	852 gas	852 gas	0%	🟰
closeLong: avg	22958 gas	21498 gas	6.7913%	🚨
closeLong: max	126406 gas	103566 gas	22.0536%	🚨
closeShort: min	765 gas	765 gas	0%	🟰
closeShort: avg	24042 gas	22248 gas	8.0636%	🚨
closeShort: max	104808 gas	87175 gas	20.2271%	🚨
initialize: min	803 gas	803 gas	0%	🟰
initialize: avg	159750 gas	159627 gas	0.0771%	🚨
initialize: max	233287 gas	233222 gas	0.0279%	🚨
openLong: min	740 gas	740 gas	0%	🟰
openLong: avg	58932 gas	42003 gas	40.3043%	🚨
openLong: max	229308 gas	224368 gas	2.2017%	🚨
openShort: min	782 gas	782 gas	0%	🟰
openShort: avg	61259 gas	49097 gas	24.7714%	🚨
openShort: max	244147 gas	218455 gas	11.7608%	🚨
removeLiquidity: min	762 gas	762 gas	0%	🟰
removeLiquidity: avg	75147 gas	63388 gas	18.5508%	🚨
removeLiquidity: max	171108 gas	123036 gas	39.0715%	🚨

This comment was automatically generated by workflow using github-action-benchmark.

[jalextowle]

This is looking great! Nice job broski. Just a few nits, and then let's .