Further fixes

[0xdomrom]

Summary

• guardrail added for spot diff feeds, constant cap of +/-10% of spot at the time of result being returned.

Will limit any sort of unexpected results in the perp marking.

• guardrail for maxExpiry added to forward feed only (more relevant to interest rate but the SM doesn't query that feed).

There can be potential exploit if you have some very long dated options (i.e. 2 year+) and interest rates are high, so adding a cap to ensure that cannot happen

• changing auction bidding to be on % of current portfolio, instead on % of original.

You run into issues around cash (i.e. funding) changing the account making it hard to actually compute the max_f properly. Means we can remove tracking "percentLiquidated" and everything is just done based on the current portfolio (no reliance on previous steps). Simplifies the logic a bit which is nice.

• related to auctions; removing allowing ANY transfers (besides getting liquidated and funding/interest being applied) when undergoing an auction.

Reasoning is: we were already blocking anything but cash. As the user getting liquidated you can liquidate your portfolio yourself -> merge to get the same effect as adding cash up to BM. You would also lose more money by donating to your portfolio and not ending auction rather than bidding on the portfolio