Extending the vault

OrderVault compiles to 24,242 of the 24,576-byte contract limit, so there are 334 bytes of headroom (forge build --sizes). That is enough for a small change but not a large one, so before adding logic, know how to make room. In rough order of how much each frees:

• Move logic into an external library. This is the biggest lever and the pattern the vault already uses: MarketGuard (the Chainlink + TWAP read and bounds) and OrderCollection (the one-time NFT-collection create) are external libraries called with delegatecall, which keeps their bytecode out of the vault. Pricing and cost maths (_gasToTinybar, _reserve, the share calculations) or the scheduling internals are the next candidates to extract the same way.
• Move the read-only views to a lens contract. The cost and status views (checkCost, fillCost, minBudget, sweepStatus, nextCheckDelay) exist for the frontend; a separate read-only "lens" contract can hold them and read the vault's storage, freeing the vault of code it never needs on-chain.
• Keep using custom errors and events (the vault has no revert strings) and keep storage structs packed (Order, SweepState) — both are already done, and both are cheap ways to stay small.

Once there is room, the usual changes:

• Add a market: add a function to script/MarketConfig.sol like usdcDai() (both tokens need Chainlink feeds), call listMarket from Deploy.s.sol, and redeploy. The frontend lists every market the vault has.
• Tune how often checks run: SweepParams (minInterval, maxInterval, maxMoveBpsPerHour). Lower maxMoveBpsPerHour costs less and reacts later. Change a live market with updateMarket.
• Tune the guard: GuardParams. MarketGuard.paramsValid keeps it meaningful: TWAP 5 min to 1 day, oracle age 60 s to 26 h, deviation and slippage at most 10%.
• Recalibrate costs: measure a few scheduled sweeps on the mirror node (gas_used in /api/v1/contracts/{id}/results/{timestamp}) and call setCosts. The frontend reads costs from the vault, so nothing else changes.
• Mainnet: add mainnet addresses to MarketConfig.sol, allow chain 295 in Deploy.s.sol (it deploys to testnet only), add the network to scaffold.config.ts, and tighten maxOracleAge to the mainnet feeds' heartbeat.