Release Geomean (token symbol GEOM) on Sepolia as a univ4_hook launch.

Token: Geomean (GEOM), total supply 1,000,000,000 GEOM with 18 decimals, minted once to the deployer.

Hook: GeomeanOracleHook, a Uniswap v4 hook on the token's native-ETH pool.

Deployment: the constructor takes one argument, the Sepolia PoolManager 0xE03A1074c86CFeDd5C142C4F04F1a1536e203543, passed as a literal in launch.json constructorArgs; getHookPermissions() returns exactly afterInitialize and beforeSwap and every other flag false (address bits 0x1080 under mask 0x3FFF), validated in the constructor; the factory mines the CREATE2 salt.

The factory's pool is currency0 = native ETH, currency1 = GEOM, LP fee 3000, tickSpacing 60, seeded with GEOM only, so the first buy lands in a pool holding no ETH and must work. State is keyed by PoolId; the base records any pool that uses the hook, which is harmless because every read names a PoolId. Callbacks are PoolManager-only (override BaseHook's internal _before/_after functions).

No owner, admin, pause or upgrade path. Tests swap through a real PoolManager; the Identity-md/univ4hook-start-template harness (BaseHookTest) provides the launch pool.

Novelty note: launch 33 already built a hand-ported v3 tick oracle (afterInitialize + afterSwap). This hook is deliberately different: it extends OpenZeppelin uniswap-hooks' BaseOracleHook (the Panoptic-derived truncated oracle shipped in the template's lib/uniswap-hooks), writes observations in beforeSwap, and keeps a truncated series in which each observation's tick may move at most MAX_ABS_TICK_DELTA = 9,116 ticks from the previous one.

That value is a literal in the constructor's call to the base, because an int24 cannot be a manifest argument.

Behaviour: afterInitialize writes the first observation; beforeSwap writes at most one observation per pool per block, before the swap moves the price, and always returns zero deltas and no fee override, so it never changes a swap's outcome and never reverts it.

Reads: the base's observe(uint32[] secondsAgos, PoolId) returning standard and truncated tick cumulatives, plus consult(PoolId, uint32 secondsAgo) returning (meanTick, truncatedMeanTick) as time-weighted arithmetic means of tick (geometric mean price) over [now - secondsAgo, now], rounded toward negative infinity as v3's OracleLibrary does; secondsAgo 0 reverts, and a window older than the oldest observation reverts.

Anyone may call increaseObservationCardinalityNext(n, poolId) to grow the ring buffer at their own gas cost; the buffer starts at 1 slot.

Views: observationState(poolId) (index, cardinality, cardinalityNext). Tests must show, across warped blocks: consult matches hand-computed means for both series; one huge single-block swap moves the standard mean far more than the truncated mean; only one observation per block; a too-old window reverts; cardinality growth takes effect after the next write; and swaps settle identically with or without the hook.

The independent adversarial review must attack: truncation arithmetic, negative-tick rounding, uint32 timestamp wrap, a beforeSwap path that could revert and brick the pool, and cardinality growth griefing.

Then a small website that charts TWAP price (GEOM per ETH and ETH per GEOM) over 1h, 6h and 24h windows for both series, sampled with one observe() call per window, shows 'not enough history' when a window is older than the buffer, and shows the buffer size with a button to grow it. Read state from hook views and events via a public Sepolia RPC with no backend; keep it to one small page; the static export has index.html in dist/.