Psi Rework Part 1: The Miracle and the Sleeper (#21584)

<img width="1701" height="292" alt="image"
src="https://github.com/user-attachments/assets/db1dbc50-1a6a-4549-b9e5-b838ec62f849"
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**This is but one of several PRs as part of Project Anabasis, and is a
necessary building-block for a Traits System and a Skills System**

This PR was essentially prompted by recent lore changes to Skrell that
weren't yet existing in the game, so I'm kicking off this as a PR to
start a series of more meaningful psionic reworks. With a focus on
Components and Signals as a way of dramatically increasing the systems
interactivity of psionics. With this PR, mobs have an effective
"Psi-Sensitivity" that can be checked by psionic effects, and influence
a wide variety of interactions.

Psi-Sensitivity is calculated based on a Signal interaction, whereby
multiple responding sources have a chance to respond to the signal and
influence the end result of the calculation. For now there still remains
a cutout specifically for owners of a Psi-Complexus(Which is just Skrell
and Antag Psions), who have a bonus to the psi-sensitivity check equal
to their PSI-RATING. That being 1 for Skrell, and 2 for antag psions.
But eventually in the future this should be replaced with a standalone
component separate from the concept of "Sending"

The other common sources of sensitivity currently are the Psionic
Receiver implant, MindShield, and Mind Blanker implants. With Psionic
Receivers giving a bonus to psi-sensitivity, and the latter two giving a
penalty to psi-sensitivity. Both MindShields and Mind Blankers are now
unified in how they interact with psionics, both using the same system
of Signals without a hardcoded check for the mindshield.

As an important distinction to make, Psi-Sensitivity is NOT the same
thing as being Psionic. Actually Psionic characters like Skrell have a
big bonus to their sensitivity. It's more a measurement of how receptive
a character is to Receiving (separate from Sending) psionic influences.
You can actually be capable of using psionic abilities, but have a
sensitivity of 0, effectively meaning such a character can "Send but not
Receive" psi influences.

- [x] I have tested this PR and have verified that it works, you're
welcome.

code/modules/shareddream/dream_entry.dm

@@ -10,11 +10,16 @@ GLOBAL_LIST_EMPTY_TYPED(dream_entries, /turf)
 
 /mob/living/carbon/human/proc/handle_shared_dreaming(var/force_wakeup = FALSE)
 	SHOULD_NOT_SLEEP(TRUE)
+	if(is_psi_blocked(src)) // Can't enter the dream if the caster is blocked from RECEIVING. It's a two-way street.
+		return
 
-	// If they're an Unconsious person with the abillity to do Skrellepathy.
-	// If either changes, they should be nocked back to the real world.
+	// This is one of the legitimate uses for has_psionics() that should be kept even though has_psionics() is deprecated.
+	// Entering the dream requires the caster be capable of SENDING.
+	var/is_psionic = has_psionics()
+
+	// Entering the dream requires that the caster either be capable of SENDING, or has a "guide" performing the SENDING on their behalf.
 	var/mob/living/carbon/human/srom_puller = srom_pulled_by?.resolve()
-	if((has_psionics() || (srom_puller && Adjacent(srom_puller))) && stat == UNCONSCIOUS && sleeping > 1)
+	if((is_psionic || (srom_puller && Adjacent(srom_puller))) && stat == UNCONSCIOUS && sleeping > 1)
 		if(!istype(bg) && client) // Don't spawn a brainghost if we're not logged in.
 			bg = new /mob/living/brain_ghost(src, src) // Generate a new brainghost.
 			if(isnull(bg)) // Prevents you from getting kicked if the brain ghost didn't spawn - geeves
@@ -27,13 +32,14 @@ GLOBAL_LIST_EMPTY_TYPED(dream_entries, /turf)
 			to_chat(bg, SPAN_WARNING("Whilst in shared dreaming, you find it difficult to hide your secrets."))
 			if(willfully_sleeping)
 				to_chat(bg, "To wake up, use the \"Awaken\" verb in the IC tab.")
-			if(!srom_pulling && has_psionics())
+			if(!srom_pulling && is_psionic)
 				var/obj/item/grab/G = r_hand
 				if(!G)
 					G = l_hand
 				if(G)
 					var/mob/living/carbon/human/victim = G.affecting
-					if(ishuman(victim) && !isSynthetic(victim) && victim.is_psi_pingable(srom_puller))
+					// Victims must be capable of RECEIVING.
+					if(!victim.is_psi_blocked(src) && ((victim.check_psi_sensitivity() > 0) || victim.has_zona_bovinae()))
 						to_chat(bg, SPAN_NOTICE("You have taken [victim] to the Srom with you."))
 						victim.srom_pulled_by = WEAKREF(src)
 						srom_pulling = WEAKREF(victim)
@@ -47,7 +53,7 @@ GLOBAL_LIST_EMPTY_TYPED(dream_entries, /turf)
 		if(istype(bg) || force_wakeup)
 			// If we choose to be asleep, keep sleeping.
 			if(willfully_sleeping && sleeping && stat == UNCONSCIOUS)
-				if(has_psionics() || srom_pulled_by)
+				if(is_psionic || srom_pulled_by)
 					sleeping = 5
 					return
 			for(var/thing in SSpsi.processing)
@@ -61,15 +67,17 @@ GLOBAL_LIST_EMPTY_TYPED(dream_entries, /turf)
 			var/mob/return_mob = src
 
 			if(srom_pulled_by)
-				if(!has_psi_aug())
+				var/sensitivity = check_psi_sensitivity()
+				if(sensitivity <= 0)
 					dizziness += 40
 					confused += 40
 					slurring += 40
 					eye_blurry += 40
 					return_text += " You feel dizzy, confused and weird..."
 				else
-					return_text += " Your augment staves off most of the post-Srom pull symptoms, but you still feel like your mind is clouded."
-				adjustBrainLoss(10)
+					return_text += " You stave off most of the post-Srom pull symptoms, but you still feel like your mind is clouded."
+				// Non-Psions can have a RECEIVING stat, so we'll account for it by giving them a leeway on the brain damage if they're sufficiently sensitive.
+				adjustBrainLoss(10 - min(10, 5 * sensitivity))
 				srom_pulled_by = null
 
 			var/mob/living/carbon/human/victim = srom_pulling?.resolve()