CHALLENGE 2: A Real Game Over Screen
====================================================================

TASK
----
Extend main.gd's _on_player_died so that, instead of only printing
"Game over," it also shows a Control-based "Game Over" screen (built
the same way as the PauseMenu) with the final score displayed on a
Label.

SETUP
-----
Add a GameOverScreen (Control) under HUD, hidden by default, with a
child Label named "FinalScoreLabel". Anchor it to "Full Rect" or
"Center" via the Layout menu, matching the PauseMenu's own setup.

SCENE ADDITION
---------------
HUD (CanvasLayer)
|-- HealthBar (ProgressBar)
|-- ScoreLabel (Label)
|-- PauseMenu (Control, hidden)
|-- GameOverScreen (Control, hidden)
    |-- FinalScoreLabel (Label)

SOLUTION CODE - game_over_screen.gd (attached to GameOverScreen)
------------------------------------------------------------------------
extends Control

func _ready() -> void:
    hide()

func show_game_over(final_score: int) -> void:
    $FinalScoreLabel.text = "Game Over - Final Score: " + str(final_score)
    show()

SOLUTION CODE - the updated part of main.gd
------------------------------------------------
func _on_player_died() -> void:
    print("Game over")
    $HUD/GameOverScreen.show_game_over(score)
    get_tree().paused = true

WHY THIS WORKS AS AN ANSWER
----------------------------
GameOverScreen starts hidden in its own _ready(), exactly like
PauseMenu (Chapter 8) - the same hide()-by-default pattern reused
for a second, unrelated Control node.

show_game_over(final_score) is a small public function on the
GameOverScreen itself, rather than main.gd reaching directly into
its Label with a hardcoded path - main.gd only needs to know
GameOverScreen has a show_game_over() method that takes a score, not
how that screen is internally structured. This mirrors the
capstone's own "main.gd wires things together, but each piece stays
independently responsible for itself" principle: GameOverScreen owns
its own FinalScoreLabel and the exact wording of its own message.

Passing score (main.gd's own running total, already updated by every
_on_coin_collected() call) directly into show_game_over() means the
final score displayed is guaranteed to be accurate at the exact
moment the player dies, with no separate score-tracking logic
duplicated inside GameOverScreen itself.