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.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;
+};