USDC approval
Trading collateral is pulled from your wallet, so USDC must be approved to the protocol once:LP vault approval is separate
The LP vault pulls from an allowance on the tranche, not TradingStorage:Claims
Both are caller-scoped: the signing key must be the account that earned them (no delegate):Builder codes
Partners routing order flow can register a builder code that collects a per-trade fee:modify_builder_code(...) (same parameters) updates it. Set builder_code in the configuration to attach your code to outgoing orders.