DeadDrops

More reliable long-range airdrops

- Fixed airdrops sometimes failing when online players are spread tens of thousands of blocks apart.
- Every eligible Overworld player now receives the same configured search-attempt budget.
- Player search order is randomized and rotates each round, keeping every player equally represented.
- Every possible landing is still checked against all eligible players.
- Drops still search between 1,000 and 5,000 blocks from a player and remain at least 1,000 blocks away from everyone.

City-first safe-terrain fallback

- DeadDrop still prefers a valid Lost Cities city landing.
- If no safe city can be found and `requireCityLocation = false`, DeadDrop repeats the same long-range race search without requiring a city.
- The old short-range fallback is no longer used by the city challenge.
- If both searches fail, the existing retry or destroyed-shipment behavior is used.
- Set `requireCityLocation = true` to keep strictly city-only drops.