USB Cables -- Connect circuits to computers/machines (#59345)

* Initial commit

* Sprites, finishing work

* More ways to detach from circuitboards

* Clear TODOs, give bots a button

* Fix qdel loop

* Designs

* It's the bots that have them

* Grammar fix

* Feedback for connecting to circuit directly

* Add USB cable design to basic circuitry

* Better naming

* Feedback

* Fix for new code

* COMSIG_CIRCUIT_ADD_COMPONENT_MANUALLY

* span procs

code/modules/wiremod/shell/bot.dm

@@ -14,5 +14,35 @@
 
 /obj/structure/bot/Initialize()
 	. = ..()
-	AddComponent(/datum/component/shell, null, SHELL_CAPACITY_LARGE)
+	AddComponent( \
+		/datum/component/shell, \
+		unremovable_circuit_components = list(new /obj/item/circuit_component/bot), \
+		capacity = SHELL_CAPACITY_LARGE, \
+		shell_flags = SHELL_FLAG_USB_PORT, \
+	)
 
+/obj/item/circuit_component/bot
+	display_name = "Bot"
+
+	/// Called when attack_hand is called on the shell.
+	var/datum/port/output/signal
+
+/obj/item/circuit_component/bot/Initialize()
+	. = ..()
+	signal = add_output_port("Signal", PORT_TYPE_SIGNAL)
+
+/obj/item/circuit_component/bot/Destroy()
+	signal = null
+	return ..()
+
+/obj/item/circuit_component/bot/register_shell(atom/movable/shell)
+	RegisterSignal(shell, COMSIG_ATOM_ATTACK_HAND, .proc/on_attack_hand)
+
+/obj/item/circuit_component/bot/unregister_shell(atom/movable/shell)
+	UnregisterSignal(shell, COMSIG_ATOM_ATTACK_HAND)
+
+/obj/item/circuit_component/bot/proc/on_attack_hand(atom/source, mob/user)
+	SIGNAL_HANDLER
+	source.balloon_alert(user, "pushed button")
+	playsound(source, get_sfx("terminal_type"), 25, FALSE)
+	signal.set_output(COMPONENT_SIGNAL)