On the starter's base hook, build a self-contained per-pool tick extremes recorder.

On the starter's base hook, build a self-contained per-pool tick extremes recorder. On each swap the hook records, for that pool, the lowest and highest tick it has ever observed and a count of swaps seen; it exposes read-only views for those three values and a flag for whether the pool has ever been observed at all.

It takes no fee, holds no privileged role, stores no owner or admin, has no reset or configuration entry point, and extends nothing that already exists — the state is append-only in the sense that extremes only ever widen.

The independent tester should take the paths the implementer would rather avoid: reads on a pool that has never swapped, the very first swap where both extremes must initialise to the same tick rather than to zero, ticks either side of zero so a signed comparison written as an unsigned one is caught, a tick that ties the current extreme rather than beating it, several swaps inside one block, and two pools recording without either seeing the other's values.

Use the harness that hands the hook a real launch pool rather than mocking the manager.