Mice can play synthesisers (#90610)

## About The Pull Request


![image](https://github.com/user-attachments/assets/9d4ce934-bb40-4b05-8d25-5bfb4998c3cd)
This PR allows mice to play synthesisers, which they will prioritise
over running away from people if they see one (but eating cheese is more
important than that).

## Why It's Good For The Game


![85786433-3946-4a94-a863-c12999082023_373x306](https://github.com/user-attachments/assets/f32c2ea3-6a85-4060-9bfb-1d8555feb35b)

## Changelog

🆑
add: Mice can play synthesisers
/🆑

code/modules/instruments/piano_synth.dm

@@ -7,12 +7,19 @@
 	allowed_instrument_ids = "piano"
 	var/circuit_type = /obj/item/circuit_component/synth
 	var/shell_capacity = SHELL_CAPACITY_SMALL
+	/// Can a mouse play this instrument?
+	var/mouse_playable = TRUE
 
 /obj/item/instrument/piano_synth/Initialize(mapload)
 	. = ..()
 	song.allowed_instrument_ids = SSinstruments.synthesizer_instrument_ids
 	AddComponent(/datum/component/shell, list(new circuit_type), shell_capacity)
 
+/obj/item/instrument/piano_synth/attack_animal(mob/living/simple_animal/user, list/modifiers)
+	if (!mouse_playable || !ismouse(user))
+		return ..()
+	song.ui_interact(user)
+
 /obj/item/instrument/piano_synth/headphones
 	name = "headphones"
 	desc = "Unce unce unce unce. Boop!"
@@ -32,6 +39,7 @@
 	instrument_range = 1
 	circuit_type = /obj/item/circuit_component/synth/headphones
 	shell_capacity = SHELL_CAPACITY_TINY
+	mouse_playable = FALSE
 
 /obj/item/instrument/piano_synth/headphones/Initialize(mapload)
 	. = ..()