Goblin Gold v3.1 is done. Both fixes are implemented, verified, and documented. Nothing was deployed and no protected file changed.

What changed

• Curator constants. New library src/IMDProtocol.sol holds the Ethereum IMD Intake v2, the IMD token, the oracle signer and the action id. The Curator constructor is now Curator(oracle, genesis, gacha). Only the compiled-in intake can answer a callback. I verified both addresses against the pinned reference and live on mainnet: the intake quotes 0.5 IMD for the oracle action, and the token reports symbol IMD.
• Thresholds. Regular v3 pools need 5 ETH per side. The GOLD/ETH v4 pool needs a 1 ETH ETH-side depth. TWAP windows and staleness are untouched.
• Payout cap. The oracle's new valueAndCap returns the TWAP value plus 5% of the pool's current ETH-side depth. The gacha snapshot commits capped values before randomness. When a cap binds on the drawn Bag, draw() splits it: the capped portion becomes a new Bag id the winner keeps or sells back, and the remainder stays listed for the depositor. Genesis quotes are capped the same way, with the surplus returned to the vault in the same transaction.
• Hash re-pinned. GACHA_RUNTIME_CODE_HASH in GoldHook now matches the final v3.1 BagGacha under the launch profile.
• Docs. README has a v3.1 summary, a payout cap section, the Curator constants, a runbook whose constructor words contain no IMD protocol address, and both remainder paths spelled out step by step. report.md records the checks.

Verification

Check	Result
Launch profile (via_ir=false, bytecode_hash=none), verifier fuzz seed	138 passed, 0 failed
Protected profile (via_ir=true), same seed	138 passed, 0 failed
forge fmt --check	pass
Mainnet fork tests via public RPC	3 passed, including the v4 PoolManager test

New tests cover the 4.99/5 ETH and 0.99/1 ETH boundaries on mocks and on the real vendored PoolManager, exact-cap versus one-wei-over splitting, keep and buyback of a split Bag, per-token caps, committed splits surviving later depth changes, the Genesis cap, and a fuzzed conservation check.

Judgment calls to note

• The genesis bound is on the ETH side only, as the brief words it. The old token-side check was dropped for the GOLD pool. Regular v3 pools still check both sides.
• A capped payout that rounds below the 0.3P small-tier floor is skipped in that snapshot rather than paid under the floor.
• The cap is read at request time, so nothing about a payout is decided after the VRF word is known.