feat: switch trigger physics volumes on and off at runtime

The ActivatePhysics trigger command was a TODO. The client activates or
deactivates the object's physics component
(LWOPhysicsSystemComponent::msgActivatePhysics, 1.10.64 0x00ccf970);
the server now does the same to phantom physics: switching it off takes
the volume out of the physics world (dpWorld::DetachEntity, without
deleting it) and makes whatever was inside leave, switching it on adds
it back and whatever is inside enters on the next step. This lets
trigger driven volumes like the monument lasers turn on and off.

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

dGame/dComponents/PhantomPhysicsComponent.h

@@ -99,6 +99,14 @@ public:
 
 	dpEntity* GetdpEntity() const { return m_dpEntity; }
 
+	/**
+	 * Switches the volume on or off (the ActivatePhysics trigger command; the client activates or deactivates
+	 * the physics component the same way). Whatever was inside leaves when it is switched off.
+	 */
+	void SetPhysicsActive(bool active);
+
+	bool GetPhysicsActive() const { return m_PhysicsActive; }
+
 	/**
 	 * Spawns an object at each of the vertices for debugging purposes
 	 */
@@ -161,6 +169,9 @@ private:
 	 */
 	dpEntity* m_dpEntity;
 
+	// Whether m_dpEntity is in the physics world
+	bool m_PhysicsActive = true;
+
 	/**
 	 * Whether or not this physics object represents an object that updates the respawn pos of an entity that crosses it
 	 */