CHALLENGE 1: A Score Label That Updates
====================================================================

TASK
----
Build a CanvasLayer containing a Label anchored to the top-left
corner. Write a script with a score variable starting at 0, a
function that adds 10 to it and updates the Label's text to
"Score: X", and call that function a few times from _ready() to
confirm it updates correctly.

SCENE STRUCTURE
----------------
Root (Node2D)
|-- HUD (CanvasLayer)
    |-- ScoreLabel (Label)  <- Layout menu > Anchor Presets > Top Left

SOLUTION CODE (attached to ScoreLabel)
-------------------------------------------
extends Label

var score: int = 0

func _ready() -> void:
    _update_label()

    add_score()
    add_score()
    add_score()

func add_score() -> void:
    score += 10
    _update_label()

func _update_label() -> void:
    text = "Score: " + str(score)

OUTPUT (visible in the running scene's top-left corner, updating live)
---------------------------------------------------------------------------
Score: 0     (briefly, on the very first frame)
Score: 10
Score: 20
Score: 30    (the final, visible state)

WHY THIS WORKS AS AN ANSWER
----------------------------
Anchoring the Label to "Top Left" via the Layout menu's preset
guarantees it sits in the same screen corner regardless of window
size, matching the chapter's own guidance to prefer a preset over
manually dragging a Control into position.

add_score() does two things every time it's called: increments the
score variable by 10, then calls the shared _update_label() helper,
which sets this Label's own text property directly (since the
script extends Label, text is already available with no $-lookup
needed - the same pattern Chapter 4 used for a script extending
Sprite2D directly). Separating the "change the data" step from the
"refresh what's displayed" step into two small functions, rather
than repeating the text = "Score: " + str(score) line inside
add_score() itself, keeps the display-update logic in exactly one
place - useful the moment a second way to change score (a bonus, a
penalty) is added later.