Stop Drugs Spam (#22197)

closes #22119

Drugs are just ungodly spammy in general, this PR puts a stop to that by
limiting the rate at which your chat can be flooded with "YOU FEEL
AWESOME!" messages.

<img width="1248" height="632" alt="image"
src="https://github.com/user-attachments/assets/3ecc81fa-4bd6-4422-b55b-7d07bbe2498e"
/>

code/modules/mob/living/carbon/carbon_defines.dm

@@ -38,6 +38,10 @@
 	var/coughedtime = null
 
 	var/willfully_sleeping = FALSE
+	/// Internal time limit based on next REALTIMEOFDAY after which a drug message can play. See #define DRUG_MESSAGE_COOLDOWN
+	var/next_drug_message = 0
+	/// Internal time limit based on next REALTIMEOFDAY after which a sobriety/crash message from drugs can play.
+	var/next_sober_message = 0
 	/// Used by Diona.
 	var/consume_nutrition_from_air = FALSE