Local, Horizon-based Hivenet in the Sea (#22907)

Vaurcae can use Hivenet in the Lemurian Sea, but only on connected
Horizon z-levels. This extends to any far sector with Hivenet echoes
disabled (currently only Crescent Expanse Uncharted), though echoes
themselves are still disabled because they mostly come from greater
Hivenet.

Supported by lore staff.

Vaurcae having Hivenet fully blocked actually wasn't pre-existing canon
but was allowed as an experiment. This PR is the preferred form of
Hivenet restriction.

" Vaurca are known to exhibit a strong sense of dread while inside the
Sea, cut off from the greater hivenet and limited only to their ship for
communicating with others."

<img width="755" height="309" alt="image"
src="https://github.com/user-attachments/assets/95b32658-5446-4b1f-be00-cc7476fcf051"
/>


Since the Fog is an anomaly already, this doesn't even have to be a
retcon.

code/modules/tgui/modules/hivenet_manifest.dm

@@ -6,7 +6,7 @@
 	all_vaurca = set_all_vaurca
 
 /datum/tgui_module/hivenet_manifest/ui_interact(var/mob/user, var/datum/tgui/ui)
-	if(is_lemurian_sea_sector())
+	if(!SSatlas.current_sector.hivenet_echoes && isNotContactLevel(user.z))
 		to_chat(user, SPAN_WARNING("You attempt to query the Hivenet, but find nothing."))
 		return
 
@@ -18,7 +18,7 @@
 /datum/tgui_module/hivenet_manifest/ui_data(mob/user)
 	var/list/data = list()
 
-	if(is_lemurian_sea_sector())
+	if(!SSatlas.current_sector.hivenet_echoes && isNotContactLevel(user.z))
 		SStgui.close_uis(src)
 		return data