feat(swapproxy): deterministic CREATE2 deployment

[david-uniswap]

Summary

Migrates SwapProxy from the fragile nonce-0 CREATE scheme to a deterministic CREATE2 deployment, so any funded key can deploy it to the same address on every chain (no privileged 0xb259… EOA at nonce 0 required).

Deterministic address (deployed on all 13 chains): 0x0000000085E102724e78eCd2F45DC9cA239Affad

• factory: 0x4e59b44847b379578588920cA78FbF26c0B4956C (Arachnid; present on all 13 chains incl. Arc, MegaETH, Robinhood)
• salt: 0xd00319ff7795e528cc1ccd28bd6e08e46a42130d69ab4992d656773ba5fb323c (vanity-mined for a 4-leading-zero-byte address, matching Permit2 / CaliburEntry)
• initcode hash: 0x342d83f4d7400dd603e2a6829db9cb032e7f62a2dda94746f2acd4e7e881bb2f

Status

Deployed on all 13 chains; each holds byte-identical 1005-byte runtime (keccak 0x24a2…7aaf). Source-verified on each block explorer (pending your review of the spot-checks):

• Etherscan-family (auto similar-match off the canonical bytecode): ethereum, optimism, base, arbitrum, celo, unichain, unichain-sepolia, sepolia
• Blockscout: soneium, zora, megaeth, robinhood, arc

Per-chain tx hashes + explorers are recorded in .swapproxy-deploy/create2.json and the registry.

Source-of-truth model (pin the contract, not the UR repo)

The CREATE2 address depends only on {factory, salt, initcode}. SwapProxy's compile closure is 5 files and it references the router only through the IUniversalRouter interface, embedding zero router bytecode — so Universal Router implementation upgrades never move this address.

We deploy the frozen canonical initcode (.swapproxy-deploy/canonical-initcode.hex, the mainnet-verified 1005-byte build) rather than recompiling from the universal-router submodule. This also sidesteps the repo's universal-router profile (optimizer_runs=1, bytecode_hash=none) which produces a divergent 964-byte build. Full rationale in .swapproxy-deploy/README.md.

What's in this PR

• script/DeploySwapProxyCreate2.s.sol — idempotent, self-checking CREATE2 deploy script.
• .swapproxy-deploy/create2.json — pinned factory/salt/initcodeHash/address/build/closure + all 13 deployments (chain → txHash → explorer → verified).
• .swapproxy-deploy/README.md — source-of-truth model + deploy/verify instructions.
• .swapproxy-deploy/canonical-initcode.hex — frozen 1031-byte initcode.
• foundry.toml — fs read permission for .swapproxy-deploy/.
• deployments/json/{chainId}.json (×13) — standard SwapProxy registry entry ({address, proxy, deploymentTxn, timestamp, commitHash}), matching the schema used by Permit2 / CaliburEntry. .md files left for CI regeneration.

Notes / open items

• New address. The legacy 0x02e5…b2a9 (nonce-0 CREATE) cannot be reproduced via CREATE2. SwapProxy is immutable + ownerless, so legacy instances stay on-chain and consumers migrate.
• The registry entries supersede the legacy 0x02e5 tracked in PR feat(deployments): track SwapProxy across 13 chains (incl. Arc 5042 + Robinhood 4663) #150/robinhood chain deployments #137 (main has no SwapProxy entries yet, so this is additive; whichever merges second reconciles old→new).
• Chain quirks captured in create2.json notes: MegaETH needed --gas-limit ~13M (estimates ~10.8M for the create), Arc needed --legacy, Robinhood deployed via cast mktx → sequencer.

🤖 Generated with Claude Code

[linear-code]

DXDOCS-125

[gretzke]

Deployments look good, however the deployment data is missing in the history section of the deployment json files.
Additionally, in order for us to be able to deploy the SwapProxy contract seamlessly in the future for new chain deployments, the contract should be deployed through the Deploy-all.s.sol script (using the deploy cli) instead of a separate deployment script. I would recommend deleting the .swapproxy-deploy directory and DeploySwapProxyCreate2.sol script and instead integrate the deployment into the script as per CONTRIBUTING.md

[david-uniswap]

Heads-up: three places this PR doesn't look like the rest of the repo, and why.

1. SwapProxy's bytecode is "frozen" and must not be regenerated.
Normally every contract in src/briefcase/deployers/… has its bytecode auto-generated from source by ./script/util/create_briefcase.sh. SwapProxy's is hardcoded, and the deployer explicitly says "do not regenerate."
Why: SwapProxy has to live at the exact same address on every chain, and that address is locked to its exact bytecode. The canonical build (done in the standalone universal-router repo) bakes in an IPFS metadata fingerprint. This monorepo compiles with that fingerprint turned off (bytecode_hash = none), so recompiling here produces the same runtime logic but a different fingerprint, which changes the bytecode and therefore the address. I verified it: a local recompile gives initcode hash 0x5927… instead of the canonical 0x342d…. So we ship the frozen bytes plus a guard test that fails if they ever change. (Permit2 doesn't hit this only because its canonical build left the fingerprint off, so it regenerates cleanly.)

2. SwapProxy is its own "protocol" in the task file, even though it's just one helper contract.
It sits as a top-level swap-proxy protocol next to permit2, v2, etc., rather than under universal-router, where its source actually lives.
Why: turning on the universal-router protocol always redeploys the Universal Router itself. We want to be able to drop SwapProxy onto a chain (including chains that already have the router) without redeploying anything else. Permit2 is modeled the same way (its own one-contract protocol), so this matches the closest precedent.

3. The deployment-history JSON entries are hand-written, not generated.
Usually forge-chronicles writes the deployments/json/<chainId>.json entries. Here they're edited by hand.
Why: SwapProxy is deployed through the deterministic CREATE2 factory, and chronicles can't attribute a factory deploy to a contract name, so it skips it (same as the Universal Router CREATE2 deploys). We backfilled the 22 existing chains by hand to match the schema; future chains will need the same manual entry.

Everything else follows the Permit2 pattern: salt in the task file, the factory deploy done in Deploy-all.s.sol's deploySwapProxy() (mirroring deployPermit2()), and a minimal deployer.