fix: AG property guard camera and foot race starter group

Two script TODOs with the live scripts shipped in the client to follow:

- AgPropGuard: accepting mission 768 before touching the orb (flag 71
  unset) plays the "MissionCam" cinematic, as L_AG_PROP_GUARD.lua does.
  Also no longer dereferences a missing Character.
- BaseFootRaceManager: joins the "FootRaceStarter" group on startup like
  L_ACT_BASE_FOOT_RACE.lua, since other foot race objects look the
  starters up through that group.

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

dScripts/ai/ACT/FootRace/BaseFootRaceManager.cpp

@@ -4,7 +4,8 @@
 #include "Entity.h"
 
 void BaseFootRaceManager::OnStartup(Entity* self) {
-	// TODO: Add to FootRaceStarter group
+	// Other foot race objects find the starters through this group (L_ACT_BASE_FOOT_RACE.lua).
+	self->AddToGroup("FootRaceStarter");
 }
 
 void BaseFootRaceManager::OnFireEventServerSide(Entity* self, Entity* sender, std::string args, int32_t param1, int32_t param2, int32_t param3) {

dScripts/ai/PROPERTY/AG/AgPropGuard.cpp

@@ -1,4 +1,5 @@
 #include "AgPropGuard.h"
+#include "GameMessages.h"
 #include "Entity.h"
 #include "Character.h"
 #include "EntityManager.h"
@@ -14,8 +15,9 @@ void AgPropGuard::OnMissionDialogueOK(Entity* self, Entity* target, int missionI
 
 	const auto state = missionComponent->GetMissionState(320);
 	if (missionID == 768 && missionState == eMissionState::AVAILABLE) {
-		if (!character->GetPlayerFlag(71)) {
-			// TODO: Cinematic "MissionCam"
+		// Players who have not touched the orb yet get a camera pan showing where it is.
+		if (character && !character->GetPlayerFlag(71)) {
+			GameMessages::SendPlayCinematic(target->GetObjectID(), u"MissionCam", target->GetSystemAddress());
 		}
 	} else if (missionID == 768 && missionState >= eMissionState::READY_TO_COMPLETE) {
 		//remove the inventory items