Add terrain hit effects, progressive damage component, and update collectable signals

scripts/components/terrain_hit_fx.gd

@@ -0,0 +1,24 @@
+class_name TerrainHitFx
+extends Node
+
+var gpu_particles: Array[GPUParticles2D] = []
+
+
+func _ready() -> void:
+	if owner is GPUParticles2D:
+		gpu_particles.append(owner)
+
+	for child in get_children():
+		if child is GPUParticles2D:
+			gpu_particles.append(child)
+
+
+func trigger_fx() -> Signal:
+	for fx in gpu_particles:
+		if fx:
+			fx.restart()
+			fx.emitting = true
+	return gpu_particles[0].finished
+	
+
+