Station announcements cleanup (#79315)

## About The Pull Request

- As the size of the announcement proc has grown over the past few PRs,
did a pass over them for readability and consistency
- Include the arg names for coders unfamiliar with the new announcement
format
- Replaced leftover hardcoded Central Command text with the command name
proc, so all announcements reflect the command name if changed by an
admin
- Replaced hard coded emergency shuttle timer text with the actual
timeleft vars, so it's correct if the timers are changed for any reason
- Darkens the dark mode blue/red headers to be more red less pink, while
staying in accessibility standards
- Adds a lower profile grey colour for automated non-Central Command
announcements

## Changelog

🆑 LT3
code: Emergency shuttle announcements no longer use hardcoded values
code: Central Command announcements now correctly use its new name when
changed
spellcheck: Consistency pass on event announcements
/🆑

code/modules/admin/verbs/adminevents.dm

@@ -224,7 +224,13 @@
 	SSshuttle.admin_emergency_no_recall = TRUE
 	SSshuttle.emergency.setTimer(0)
 	SSshuttle.emergency.mode = SHUTTLE_DISABLED
-	priority_announce("Warning: Emergency Shuttle uplink failure, shuttle disabled until further notice.", "Emergency Shuttle Uplink Alert", 'sound/misc/announce_dig.ogg')
+	priority_announce(
+		text = "Emergency Shuttle uplink failure, shuttle disabled until further notice.",
+		title = "Uplink Failure",
+		sound = 'sound/misc/announce_dig.ogg',
+		sender_override = "Emergency Shuttle Uplink Alert",
+		color_override = "grey",
+	)
 
 /client/proc/admin_enable_shuttle()
 	set category = "Admin.Events"
@@ -250,7 +256,13 @@
 	if(SSshuttle.last_call_time < 10 SECONDS && SSshuttle.last_mode != SHUTTLE_IDLE)
 		SSshuttle.last_call_time = 10 SECONDS //Make sure no insta departures.
 	SSshuttle.emergency.setTimer(SSshuttle.last_call_time)
-	priority_announce("Warning: Emergency Shuttle uplink reestablished, shuttle enabled.", "Emergency Shuttle Uplink Alert", 'sound/misc/announce_dig.ogg')
+	priority_announce(
+		text = "Emergency Shuttle uplink reestablished, shuttle enabled.",
+		title = "Uplink Restored",
+		sound = 'sound/misc/announce_dig.ogg',
+		sender_override = "Emergency Shuttle Uplink Alert",
+		color_override = "green",
+	)
 
 /client/proc/admin_hostile_environment()
 	set category = "Admin.Events"