feat: add missing force field, jetpack NPC and Skullkin volume scripts

Ported from the live server scripts that ship with the client:

- scripts\ai\LS\ForceFieldEffect.lua (LEGO Club and Starbase 3001 force
  fields): plays effect 3671 "cast" on whatever touches the phantom.
- scripts\ai\NP\L_NPC_NP_JETPACK_GUY.lua (jetpack ambient NPCs): plays
  the object's "launch" effect when used.
- scripts\02_server\Map\AM\L_SKELETON_SPAWNER_VOLUME.lua (Crux Prime
  Skullkin area): with 10 or more players in the volume the Skullkin
  engineer, miner and patroller networks maintain 2/6/6 instead of
  1/4/4, with a 60 second cooldown between changes and a catch-up check
  when it ends. Only players are counted, and the count never goes
  below zero.

WBL_Enemy_Grabbler.lua only sets wander variables for the old Lua
movement AI, so it joins the other alpha wander scripts in the excluded
list instead of logging as missing.

Refs #746

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dScripts/02_server/Map/AM/AmSkeletonSpawnerVolume.cpp

@@ -0,0 +1,75 @@
+#include "AmSkeletonSpawnerVolume.h"
+
+#include "Entity.h"
+#include "dZoneManager.h"
+#include "Spawner.h"
+
+namespace {
+	const std::u16string TotalPlayers = u"TotalPlayers";
+	const std::u16string SpawnStateMax = u"SpawnStateMax";
+	const std::u16string JustChanged = u"JustChanged";
+
+	void SetNumAndReset(const std::string& spawnerName, const int32_t num) {
+		for (auto* const spawner : Game::zoneManager->GetSpawnersByName(spawnerName)) {
+			spawner->SetNumToMaintain(num);
+			spawner->Reset();
+		}
+	}
+}
+
+void AmSkeletonSpawnerVolume::OnStartup(Entity* self) {
+	self->SetVar<int32_t>(TotalPlayers, 0);
+	self->SetVar<bool>(SpawnStateMax, false);
+	self->SetVar<bool>(JustChanged, false);
+}
+
+void AmSkeletonSpawnerVolume::OnCollisionPhantom(Entity* self, Entity* target) {
+	if (!target || !target->IsPlayer()) return;
+
+	const auto totalPlayers = self->GetVar<int32_t>(TotalPlayers) + 1;
+	self->SetVar<int32_t>(TotalPlayers, totalPlayers);
+
+	if (totalPlayers >= ChangeNum && !self->GetVar<bool>(JustChanged) && !self->GetVar<bool>(SpawnStateMax)) {
+		SetSpawnCounts(self, true);
+	}
+}
+
+void AmSkeletonSpawnerVolume::OnOffCollisionPhantom(Entity* self, Entity* target) {
+	if (!target || !target->IsPlayer()) return;
+
+	const auto totalPlayers = std::max(self->GetVar<int32_t>(TotalPlayers) - 1, 0);
+	self->SetVar<int32_t>(TotalPlayers, totalPlayers);
+
+	if (totalPlayers < ChangeNum && !self->GetVar<bool>(JustChanged) && self->GetVar<bool>(SpawnStateMax)) {
+		SetSpawnCounts(self, false);
+	}
+}
+
+void AmSkeletonSpawnerVolume::OnTimerDone(Entity* self, std::string timerName) {
+	if (timerName != "StateChange") return;
+
+	self->SetVar<bool>(JustChanged, false);
+
+	// Catch up on any change that was held back while the counts were cooling down.
+	const auto totalPlayers = self->GetVar<int32_t>(TotalPlayers);
+	const auto isMax = self->GetVar<bool>(SpawnStateMax);
+	if (!isMax && totalPlayers >= ChangeNum) {
+		SetSpawnCounts(self, true);
+	} else if (isMax && totalPlayers < ChangeNum) {
+		SetSpawnCounts(self, false);
+	}
+}
+
+void AmSkeletonSpawnerVolume::SetSpawnCounts(Entity* self, const bool max) {
+	self->SetVar<bool>(SpawnStateMax, max);
+	self->SetVar<bool>(JustChanged, true);
+	self->AddTimer("StateChange", ChangeCooldown);
+
+	// There are 6 engineer and 6 miner spawner networks.
+	for (int32_t i = 1; i <= 6; i++) {
+		SetNumAndReset("Skullkin_Engineer_" + std::to_string(i), max ? 2 : 1);
+		SetNumAndReset("Skullkin_Miner_" + std::to_string(i), max ? 6 : 4);
+	}
+
+	SetNumAndReset("Skullkin_Patrollers", max ? 6 : 4);
+}

dScripts/02_server/Map/AM/AmSkeletonSpawnerVolume.h

@@ -0,0 +1,21 @@
+#pragma once
+#include "CppScripts.h"
+
+// A volume over the Skullkin area of Crux Prime that spawns more Skullkin while many players are in it.
+class AmSkeletonSpawnerVolume : public CppScripts::Script {
+public:
+	void OnStartup(Entity* self) override;
+	void OnCollisionPhantom(Entity* self, Entity* target) override;
+	void OnOffCollisionPhantom(Entity* self, Entity* target) override;
+	void OnTimerDone(Entity* self, std::string timerName) override;
+
+private:
+	// Sets the spawner networks to the higher or lower counts.
+	static void SetSpawnCounts(Entity* self, bool max);
+
+	// Players needed in the volume for the higher counts.
+	static constexpr int32_t ChangeNum = 10;
+
+	// Seconds after a change before the counts may change again.
+	static constexpr float ChangeCooldown = 60.0f;
+};

dScripts/02_server/Map/AM/CMakeLists.txt

@@ -1,5 +1,6 @@
 set(DSCRIPTS_SOURCES_02_SERVER_MAP_AM 
 	"AmConsoleTeleportServer.cpp"
+	"AmSkeletonSpawnerVolume.cpp"
 	"RandomSpawnerFin.cpp"
 	"RandomSpawnerPit.cpp"
 	"RandomSpawnerStr.cpp"