Stake pUSD, earn real interest

spUSD will be an ERC-4626 vault: deposit pUSD, it's auto-supplied across the stock-collateral Morpho markets above, and earns the real interest borrowers pay to hold their position open. Share price rises as that interest accrues — no separate claim step, no T-bill leg, no custody surface. Wired up the same way loopr's Steakhouse-vault staking works today, once the vault contract is live.