Hoard

The gold pile, the nest scrape beside it, and the clutch in the scrape.

The pile is a thermal battery: Sim.hoardStep integrates its temperature against the air (sheltered when Game.inCave says so), the sun, and any dragon lying on it. A cold pile steals body heat; a charged one pays it back and its thermal mass rides out the night. Its rendered size comes from dragon.fauna's hoard(mass), whose hemisphere radius is the same one Sim.hoardSurfaceArea integrates — the geometry you see IS the geometry the physics reads.

The clutch: Sim.nestStep + Sim.incubationRate. A dragon standing within ~6 m of the scrape broods it (its core temperature drives the brood patch); an unguarded clutch drifts toward the pile/air and progress decays. Incubation progress is clamped to [0, 1]; at 1.0 the clutch fledges — Game.milestones.clutch is set and the roster lays a fresh clutch after a quiet interval. Raptors and wolves remove eggs through stealEgg().

Publishes the flight-controller contract Game.nearestHoard(x, z) (contact-gated: returns the pile only when (x, z) is actually on it) and Game.hoards for the egg thieves.

Multiplayer/persistence: the lowest peer id integrates; state mirrors through runtime_data.world under dragon/hoard/main, so every peer converges on one ledger and the hoard survives restarts.