SIP-378

[sunnyvempati]

https://sips.synthetix.io/sips/sip-378/

1 & 2 are in this PR

3: ~https://github.com/Synthetixio/synthetix-v3/pull/2110~ cherrypicked here from fix-zero-fee-to-referrer branch

[kaleb-keny]

Hey @sunnyvempati @leomassazza in order to avoid getting ourselves into another sip-378 situation, can we please setup a test that checks only the necessary number of feeds needs an update for settle / flag scenarios:

1. On settle events:

• setup perp market with 5 active markets.
• make all markets Default stale but not 1 month stale
• get user to commit to an order and update only feeds that are proposed to be updated with 7421 error
• get keeper to settle the order, only 1 feed is supposed to be updated. Otherwise test failed.

1. On flag events:

• setup perp market with 5 active markets
• setup a user position in 2 of the markets
• make all markets Default stale but not 1 month stale
• liquidation should ask for 2 market price updates (the users' positions). Otherwise test fails

Writing this with https://github.com/Synthetixio/synthetix-v3/pull/1991#discussion_r1588982988 in mind, which i am certain will cause issues, due to DEFAULT tolerance being users in the multi-collateral PR on liquidation

[noahlitvin]

We all saw tests green, but was hanging on SSH in circleci for some reason, so I'm merging.