feat: experimental MetaSwap order delegation manager

[hanzel98]

Summary

• Experimental purpose-specific MetaSwapOrderDelegationManager for two MetaSwap flows (not a drop-in for the generic DelegationManager).
• Also includes experimental flexible-only prototypes (Hookless, ExecutionBuilder) under src/experiments/ for comparison.

Intent	Product	User signs	Redeemer may change
ExactCalldata	Gasless exact swap	Full batch hash	Nothing
FlexibleSettlement	Limit order	Economics + approval shape	Route / aggregatorId only

Redemption gas (EIP-7702)

Measured with gasleft() immediately around redeemDelegations. Each old/new pair executes the same swap shape from a one-element root delegation with an ECDSA signature and zero starting output-token balance. Numbers include the manager call and exclude top-level transaction intrinsic calldata gas.

Purpose	Swap shape	Existing DelegationManager path	Existing gas	Order gas	Saving
Gasless exact swap	Native swap	ExactExecutionBatch + LimitedCalls(1)	167,475	96,618	42.3%
Gasless exact swap	approve + swap	ExactExecutionBatch + LimitedCalls(1)	230,987	152,242	34.1%
Gasless exact swap	reset + approve + swap	ExactExecutionBatch + LimitedCalls(1)	244,355	157,710	35.5%
Flexible limit order	Native swap	MetaSwapFlexibleSettlementEnforcer	143,414	101,730	29.1%
Flexible limit order	approve + swap	MetaSwapFlexibleSettlementEnforcer	200,783	158,990	20.8%
Flexible limit order	reset + approve + swap	MetaSwapFlexibleSettlementEnforcer	207,974	166,072	20.1%

Exact orders save 34–42% by removing generic delegation loops, external hook calls, full execution terms, and LimitedCallsEnforcer state/event costs. Flexible orders save 20–29% while retaining approval-shape, swap-calldata, and output-delta validation. The compact redemption event is part of the measured saving; the generic manager emits the full delegation.

Included

• Contracts: order manager + shared base + two flexible prototypes
• Docs: documents/MetaSwapSpecializedDelegationManagers.md
• Tests: order + specialized suites, including native, approve, and reset-approve gas comparisons
• Deploy: script/DeployMetaSwapOrderDelegationManager.s.sol
• Verify: script/verification/verify-metaswap-order-delegation-manager.sh

Limits

• One root delegation, one self-caveat, batch/default only
• No chains / try-mode / pause / enableDelegation
• Gasless expiry remains off-chain
• ECDSA first; accounts with code fall back to ERC-1271

Supersedes naming in #206 (feat/metaswap-intent-delegation-manager).

Test plan

• 32 focused MetaSwapOrderDelegationManagerTest tests pass
• Equivalent native, approve, and reset-approve redemption benchmarks cover both intents
• Dry-run script/DeployMetaSwapOrderDelegationManager.s.sol
• Confirm verify script reads META_SWAP_ORDER_DELEGATION_MANAGER_ADDRESS

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Note

High Risk
New on-chain paths authorize MetaSwap batches, ERC-20 approvals, and min-output checks via balance deltas, with documented trust in delegates, MetaSwap, and unrelated balance increases; mistakes could affect user funds despite extensive tests.

Overview
Adds an experimental MetaSwap stack: purpose-built redemption managers, several MetaSwap caveat enforcers, deploy/verify wiring, docs, and broad Forge coverage (including gas benchmarks vs the generic DelegationManager).

MetaSwapOrderDelegationManager (with MetaSwapDelegationManagerBase) is the main product path for EIP-7702 accounts. It keeps the familiar redeemDelegations shape but only allows one root delegation, one self-referential caveat, and batch/default execution. ExactCalldata commits to keccak256(execution batch) for gasless exact swaps; FlexibleSettlement binds swap economics (tokens, amounts, approval shape, recipient, min output) while leaving MetaSwap route/aggregatorId to the redeemer. Enforcement is internal—no external caveat hooks—aimed at ~20–42% lower redemption gas than ExactExecutionBatch + LimitedCalls(1) or MetaSwapFlexibleSettlementEnforcer.

Also ships flexible settlement enforcers for the generic manager path: MetaSwapFlexibleSettlementEnforcer (one-shot consumption + min output on recipient balance), plus calldata-shape helpers (MetaSwapBatchCalldataEnforcer, MetaSwap7702CalldataEnforcer, MetaSwapApproveSwapEnforcer). MetaSwapFlexibleSettlementEnforcer is added to DeployCaveatEnforcers.s.sol and documented in CaveatEnforcers.md.

Under src/experiments/, prototype managers (Hookless, ExecutionBuilder, GaslessSwapDelegationManager, MetaSwapMinimalDelegationManager) compare hook-based vs inlined validation. documents/MetaSwapSpecializedDelegationManagers.md, DeployMetaSwapOrderDelegationManager.s.sol, verify-metaswap-order-delegation-manager.sh, and META_SWAP_ORDER_DELEGATION_MANAGER_ADDRESS in .env.example support deployment and verification.

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