Hosts can lock config options from admins (#31254)

* Hosts can lock config options from admins

* Optimization of LoadEntries

a very very very small one

code/controllers/configuration/configuration.dm

@@ -74,6 +74,10 @@ GLOBAL_PROTECT(config_dir)
 		if(copytext(L, 1, 2) == "#")
 			continue
 
+		var/lockthis = copytext(L, 1, 2) == "@"
+		if(lockthis)
+			L = copytext(L, 2)
+
 		var/pos = findtext(L, " ")
 		var/entry = null
 		var/value = null
@@ -96,6 +100,9 @@ GLOBAL_PROTECT(config_dir)
 			log_config("Found [entry] in [filename] when it should have been in [E.resident_file]! Ignoring.")
 			continue
 
+		if(lockthis)
+			E.protection |= CONFIG_ENTRY_LOCKED
+
 		var/validated = E.ValidateAndSet(value)
 		if(!validated)
 			log_config("Failed to validate setting \"[value]\" for [entry]")