tehAon’s ProjectZ-WalkerSims Boss Fix

First release. Game V3.0.0 – V3.1.
Built on the rebalance idea ProjectZ's own author posted on the ProjectZ Discord: don't scale the
bosses down in place, **move them out of the small zombie night pools into the hostile-animal
night pools**, which are 80–94% `none`. His file is additive and can't be dropped on a current
install (it never removes the originals, and 3 of its 8 wasteland ops target groups that no
longer exist), so this does the same thing against what ProjectZ ships today.
- Removes ProjectZ's bosses from `ZombiesSnowNight`, `ZombiesDesertNight` and
`ZombiesBurntForestNight` — those groups return to exactly their vanilla weights
(1.90 / 1.60 / 1.20), taking them from 72.5% / 65.2% / 72.1% boss to **0%**.
- Re-adds them to `EnemyAnimalsSnowNight`, `EnemyAnimalsDesertNight` and
`EnemyAnimalsBurntForestNight` at BlackRabbit's own halved weights — **2.7% / 1.5% / 1.5%** of
those pools (19.7% / 7.0% / 13.4% of non-`none` picks).
- Trims `ZombiesWasteland` (day) 29.8% → **8.6%**, tighter than his pass, which left it at 18.2%.
- Trims `ZombiesWastelandNight` 6.8% → **3.5%** using his numbers.
- Leaves `ZombiesWastelandDowntown` (2.6%), `EnemyAnimalsForest` (0.4%), POI sleepers, blood moon
waves and `ZombiesBoss` untouched.
- Does not port `ZombiesWastelandNight2`, `ZombiesWastelandNightNoBears` or
`ZombiesWastelandNight2NoBears` — no such groups exist in vanilla V3.0.0–V3.1 or ProjectZ 3.0.
- `tools/validate_xml.py` merges vanilla + ProjectZ the way load order does, applies every op, and
fails if any matches nothing or if a watched group is still over 25% boss of real spawns.
`package.sh` runs it as the build step.
Verified: 38/38 ops resolve and produce the shares above. Load-tested on a 3.0.1 dedicated server
with the real ProjectZ pack. Not yet playtested in a live game.

Retarget: match ProjectZ's boss **rate**, not its boss share. Game V3.0.0 – V3.1.
0.1.0 fixed the biome night pools but aimed at the wrong number. Reading the vanilla spawner
(`SpawnManagerBiomes`, `ChunkAreaBiomeSpawnData`) showed ProjectZ's boss *share* is already
19–25% of enemy spawns in those biomes — higher than WalkerSim's. What keeps it playable is
throughput: `maxcount="1"` on a 1.1-day respawn, and `DecCount(_killed: true)` drops `maxCount`
again when you kill one. That works out to **0.6–1.0 boss encounters per in-game day**. Since
WalkerSim's throughput is one to two orders of magnitude higher, matching that rate means driving
the share far *below* vanilla's, not up to it. 0.1.0 landed around 10× vanilla.
Also found: WalkerSim assigns an agent's entity class **once** and reuses it on every respawn.
The 30-in-game-minute reroll guard only fires when `agent.TimeToDie` is a real value, and it is
`ulong.MaxValue` for anything that is not `EntityHuman`/`EntityZombieDog` — so for bosses it never
fires. Boss agents accumulate and wander. Pine forest, with **zero** bosses in its day groups,
measured the same boss density as snow at night, 99.5% of it classed in other biomes. This is also
why day and night converge, and why no entitygroup edit can restore "daytime is safer".
- Bosses now removed from `ZombiesWasteland` (day) as well — all four shared pools return to exact
vanilla weights: **1.90 / 1.60 / 1.20 / 2.05**.
- New dedicated groups `tehAonBossSnowNight`, `tehAonBossDesertNight`,
`tehAonBossBurntForestNight`, `tehAonBossWastelandDay` — each totals 100, ~99.9% `none`, with
ProjectZ's own relative weights preserved. Reached by new `Config/spawning.xml` entries that
mirror the vanilla entry's `time` and POI tags.
- **Fixes a regression in 0.1.0**: the hostile-animal night pools it used carry no POI tags, so
bosses reached snow and desert **towns** at night, where vanilla ProjectZ has none
(0% → 1.9% snow, 0% → 1.2% desert). Back to **0.00%**.
- **Fixes a m…