feat: add MetaSwap delegation manager for gasless swaps and limit orders

[hanzel98]

Summary

• Adds MetaSwapOrderDelegationManager for the two MetaSwap flows: gasless swaps and limit orders.
• A gasless swap signs the exact batch hash, so the redeemer cannot change the calls. A limit order signs the settlement bounds, and the redeemer supplies the route.
• Redemption costs less because these flows no longer go through the generic delegation loop and external caveat hooks. The checks those flows need are enforced by the manager.

Flow	User signs	Redeemer may change
Gasless swap	The batch hash	Nothing
Limit order	Tokens, amounts, approval shape, recipient, redeemers, optional timestamp and id	The route and aggregator id

A limit order still requires a listed redeemer, checks the approval and swap shape, and requires the signed minimum output. disabledDelegations remains the one-shot for both flows. A failed fill rolls back.

Gas

Estimated transaction gas: 21,000 plus calldata plus execution. Each row is the same swap.

Gasless swaps

Today the signed call is a self-call into the 7702 account, and that call runs the batch. The order manager signs the batch hash and runs the batch directly.

Swap	Delegation Manager self-call	Order manager	Saved
Native ETH in, token out	207,406	119,846	87,560 (42.2%)
Token in, native ETH out	244,371	150,307	94,064 (38.5%)
Token in, token out	267,138	172,834	94,304 (35.3%)
Token in, token out, with reset	280,704	179,889	100,815 (35.9%)

Limit orders

Today this is separate root delegations on DelegationManager: an approval, then a swap. The flexible settlement enforcer collapses that into one delegation. This manager does too, and it is cheaper than both.

Swap	Separate roots	Delegation Manager + flexible settlement enforcer	Order manager
Native ETH in, token out	400,781	180,323	154,924
Token in, native ETH out	547,368	230,757	185,275
Token in, token out	553,429	235,372	209,780
Token in, token out, with reset	578,824	244,078	218,447

Saved against the separate roots:

Swap	Enforcer	Order manager
Native ETH in, token out	220,458 (55.0%)	245,857 (61.3%)
Token in, native ETH out	316,611 (57.8%)	362,093 (66.2%)
Token in, token out	318,057 (57.5%)	343,649 (62.1%)
Token in, token out, with reset	334,746 (57.8%)	360,377 (62.3%)

The order manager is also cheaper than the enforcer on every shape:

Swap	Saved	Percent
Native ETH in, token out	25,399	14.1%
Token in, native ETH out	45,482	19.7%
Token in, token out	25,592	10.9%
Token in, token out, with reset	25,631	10.5%

Scope

• One root delegation, one caveat, batch mode
• Gasless expiry stays off-chain. A limit order can set a timestamp window
• id == 0 is one-shot by delegation hash. A non-zero id also blocks sibling orders that share it. Cancelling does not burn the id
• No delegation chains, try mode, pause, or enableDelegation
• An EIP-7702 account that uses this manager redeems through it instead of DelegationManager

Test plan

• MetaSwapOrderDelegationManagerTest passes, including both flows and the redemption guards
• Dry-run script/DeployMetaSwapOrderDelegationManager.s.sol
• Confirm the verify script reads META_SWAP_ORDER_DELEGATION_MANAGER_ADDRESS

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