Allows admins to see previously obsessed players, minor obsession code cleanup (#86609)

## About The Pull Request

Closes #86603 by adding a dummy antag datum that will be added to
everyone who lost the trauma before losing the antag datum (i.e. from
being "cured" from trauma in one way or another)
Also added defines for obsession objectives

## Changelog
🆑
code: Minor obsession code cleanup
admin: Admins can now see players who were previously obsessed but had
been "cured" from the trauma
/🆑

code/datums/brain_damage/creepy_trauma.dm

@@ -66,7 +66,8 @@
 
 /datum/brain_trauma/special/obsessed/on_lose()
 	..()
-	owner.mind.remove_antag_datum(/datum/antagonist/obsessed)
+	if (owner.mind.remove_antag_datum(/datum/antagonist/obsessed))
+		owner.mind.add_antag_datum(/datum/antagonist/former_obsessed)
 	owner.clear_mood_event("creeping")
 	if(obsession)
 		log_game("[key_name(owner)] is no longer obsessed with [key_name(obsession)].")

code/modules/antagonists/obsessed/obsessed.dm

@@ -1,3 +1,9 @@
+#define OBSESSED_OBJECTIVE_SPEND_TIME "spend_time"
+#define OBSESSED_OBJECTIVE_POLAROID "polaroid"
+#define OBSESSED_OBJECTIVE_HUG "hug"
+#define OBSESSED_OBJECTIVE_HEIRLOOM "heirloom"
+#define OBSESSED_OBJECTIVE_JEALOUS "jealous"
+
 /datum/antagonist/obsessed
 	name = "Obsessed"
 	show_in_antagpanel = TRUE
@@ -13,8 +19,23 @@
 	preview_outfit = /datum/outfit/obsessed
 	hardcore_random_bonus = TRUE
 	stinger_sound = 'sound/ambience/antag/creepalert.ogg'
+	/// How many objectives should be generated
+	var/objectives_to_generate = 3
+	/// Brain trauma that causes the obsession
 	var/datum/brain_trauma/special/obsessed/trauma
 
+/// Dummy antag datum that will show the cured obsessed to admins
+/datum/antagonist/former_obsessed
+	name = "Former Obsessed"
+	show_in_antagpanel = FALSE
+	show_name_in_check_antagonists = TRUE
+	antagpanel_category = ANTAG_GROUP_CREW
+	show_in_roundend = FALSE
+	count_against_dynamic_roll_chance = FALSE
+	silent = TRUE
+	can_elimination_hijack = ELIMINATION_PREVENT
+	antag_flags = FLAG_FAKE_ANTAG
+
 /datum/antagonist/obsessed/admin_add(datum/mind/new_owner,mob/admin)
 	var/mob/living/carbon/C = new_owner.current
 	if(!istype(C))
@@ -72,7 +93,7 @@
 	H.regenerate_icons()
 
 /datum/antagonist/obsessed/forge_objectives(datum/mind/obsessionmind)
-	var/list/objectives_left = list("spendtime", "polaroid", "hug")
+	var/list/objectives_left = list(OBSESSED_OBJECTIVE_SPEND_TIME, OBSESSED_OBJECTIVE_POLAROID, OBSESSED_OBJECTIVE_HUG)
 	var/datum/objective/assassinate/obsessed/kill = new
 	kill.owner = owner
 	kill.target = obsessionmind
@@ -84,44 +105,44 @@
 			family_heirloom = heirloom_quirk.heirloom?.resolve()
 			break
 	if(family_heirloom)
-		objectives_left += "heirloom"
+		objectives_left += OBSESSED_OBJECTIVE_HEIRLOOM
 
 	// If they have no coworkers, jealousy will pick someone else on the station. This will never be a free objective.
 	if(!is_captain_job(obsessionmind.assigned_role))
-		objectives_left += "jealous"
+		objectives_left += OBSESSED_OBJECTIVE_JEALOUS
 
-	for(var/i in 1 to 3)
-		var/chosen_objective = pick(objectives_left)
-		objectives_left.Remove(chosen_objective)
+	for(var/i in 1 to objectives_to_generate)
+		var/chosen_objective = pick_n_take(objectives_left)
 		switch(chosen_objective)
-			if("spendtime")
+			if(OBSESSED_OBJECTIVE_SPEND_TIME)
 				var/datum/objective/spendtime/spendtime = new
 				spendtime.owner = owner
 				spendtime.target = obsessionmind
 				objectives += spendtime
-			if("polaroid")
+			if(OBSESSED_OBJECTIVE_POLAROID)
 				var/datum/objective/polaroid/polaroid = new
 				polaroid.owner = owner
 				polaroid.target = obsessionmind
 				objectives += polaroid
-			if("hug")
+			if(OBSESSED_OBJECTIVE_HUG)
 				var/datum/objective/hug/hug = new
 				hug.owner = owner
 				hug.target = obsessionmind
 				objectives += hug
-			if("heirloom")
+			if(OBSESSED_OBJECTIVE_HEIRLOOM)
 				var/datum/objective/steal/heirloom_thief/heirloom_thief = new
 				heirloom_thief.owner = owner
 				heirloom_thief.target = obsessionmind//while you usually wouldn't need this for stealing, we need the name of the obsession
 				heirloom_thief.steal_target = family_heirloom
 				objectives += heirloom_thief
-			if("jealous")
+			if(OBSESSED_OBJECTIVE_JEALOUS)
 				var/datum/objective/assassinate/jealous/jealous = new
 				jealous.owner = owner
 				jealous.target = obsessionmind//will reroll into a coworker on the objective itself
 				objectives += jealous
 
 	objectives += kill//finally add the assassinate last, because you'd have to complete it last to greentext.
+
 	for(var/datum/objective/O in objectives)
 		O.update_explanation_text()
 
@@ -278,3 +299,9 @@
 		explanation_text = "Steal [target.name]'s family heirloom, [steal_target] they cherish."
 	else
 		explanation_text = "Free Objective"
+
+#undef OBSESSED_OBJECTIVE_SPEND_TIME
+#undef OBSESSED_OBJECTIVE_POLAROID
+#undef OBSESSED_OBJECTIVE_HUG
+#undef OBSESSED_OBJECTIVE_HEIRLOOM
+#undef OBSESSED_OBJECTIVE_JEALOUS