feat(display): enable borderless fullscreen by default, F11/Alt+Enter toggle, and menu button

scripts/main_menu.gd

@@ -67,6 +67,17 @@ static func _build_label() -> String:
 	return "dev"
 
 
+static func _update_fs_button(btn: Button) -> void:
+	if DisplayServer.get_name() == "headless":
+		btn.text = "⛶ Fullscreen (F11)"
+		return
+	var m := DisplayServer.window_get_mode()
+	if m == DisplayServer.WINDOW_MODE_FULLSCREEN or m == DisplayServer.WINDOW_MODE_EXCLUSIVE_FULLSCREEN:
+		btn.text = "🗗 Windowed (F11)"
+	else:
+		btn.text = "⛶ Fullscreen (F11)"
+
+
 func _ready() -> void:
 	var v := Label.new()
 	v.text = "build %s" % _build_label()
@@ -87,6 +98,20 @@ func _ready() -> void:
 	v.mouse_filter = Control.MOUSE_FILTER_IGNORE
 	add_child(v)
 
+	var fs_btn := Button.new()
+	fs_btn.set_anchors_preset(Control.PRESET_TOP_RIGHT)
+	fs_btn.offset_left = -160
+	fs_btn.offset_top = 10
+	fs_btn.offset_right = -10
+	fs_btn.offset_bottom = 38
+	fs_btn.add_theme_font_size_override("font_size", 12)
+	_update_fs_button(fs_btn)
+	fs_btn.pressed.connect(func():
+		Session.toggle_fullscreen()
+		_update_fs_button(fs_btn)
+	)
+	add_child(fs_btn)
+
 	# Cache node references.
 	_auth_buttons_row = $CenterContainer/VBoxContainer/AuthButtonsRow
 	_login_button = $CenterContainer/VBoxContainer/AuthButtonsRow/LoginButton

scripts/session.gd

@@ -46,3 +46,28 @@ func clear() -> void:
 	port = 0
 	active = false
 	editing = false
+
+
+func _unhandled_input(event: InputEvent) -> void:
+	if event is InputEventKey and event.pressed and not event.echo:
+		if event.keycode == KEY_F11 or (event.keycode == KEY_ENTER and event.alt_pressed):
+			toggle_fullscreen()
+			get_viewport().set_input_as_handled()
+
+
+func toggle_fullscreen() -> void:
+	if DisplayServer.get_name() == "headless":
+		return
+	var current_mode := DisplayServer.window_get_mode()
+	if current_mode == DisplayServer.WINDOW_MODE_FULLSCREEN or current_mode == DisplayServer.WINDOW_MODE_EXCLUSIVE_FULLSCREEN:
+		DisplayServer.window_set_mode(DisplayServer.WINDOW_MODE_WINDOWED)
+		var screen_id := DisplayServer.window_get_current_screen()
+		var screen_rect := DisplayServer.screen_get_usable_rect(screen_id)
+		var target_w := mini(1280, int(screen_rect.size.x * 0.9))
+		var target_h := mini(720, int(screen_rect.size.y * 0.9))
+		DisplayServer.window_set_size(Vector2i(target_w, target_h))
+		var pos := screen_rect.position + (screen_rect.size - Vector2i(target_w, target_h)) / 2
+		DisplayServer.window_set_position(pos)
+	else:
+		DisplayServer.window_set_mode(DisplayServer.WINDOW_MODE_FULLSCREEN)
+

scripts/smoke_test_main_menu_full_flow.gd

@@ -25,7 +25,7 @@ func _run() -> void:
 	var username_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/UsernameEdit")
 	var password_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/PasswordEdit")
 	var email_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/EmailEdit")
-	var dob_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/DobEdit")
+	var over_18_check: CheckBox = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/Over18Check")
 	var auth_button: Button = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthButton")
 	var auth_mode_label: Label = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthModeLabel")
 	var welcome_label: Label = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/WelcomeLabel")
@@ -46,7 +46,7 @@ func _run() -> void:
 	username_edit.text = "mainmenu_e2e_%d" % unique_id
 	password_edit.text = "TestPass123!"
 	email_edit.text = "mainmenu_e2e_%d@test.example.com" % unique_id
-	dob_edit.text = "1990-01-01"
+	over_18_check.button_pressed = true
 
 	# Call the submit handler directly (awaited) rather than via
 	# auth_button.pressed.emit() -- a synthetic .emit() in --script/
@@ -68,7 +68,7 @@ func _run() -> void:
 	_check("Username edit hidden after auth", not username_edit.visible)
 	_check("Password edit hidden after auth", not password_edit.visible)
 	_check("Email edit hidden after auth", not email_edit.visible)
-	_check("DOB field hidden after auth", not dob_edit.visible)
+	_check("Over18 checkbox hidden after auth", not over_18_check.visible)
 	_check("Auth button hidden after auth", not auth_button.visible)
 	_check("Auth mode label hidden after auth", not auth_mode_label.visible)
 	_check("Welcome label contains username", welcome_label.text.begins_with("Welcome, mainmenu_e2e_"))

scripts/smoke_test_main_menu_ui.gd

@@ -31,7 +31,7 @@ func _run() -> void:
 	var auth_panel: PanelContainer = instance.get_node("CenterContainer/VBoxContainer/AuthPanel")
 	var auth_mode_label: Label = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthModeLabel")
 	var email_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/EmailEdit")
-	var dob_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/DobEdit")
+	var over_18_check: CheckBox = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/Over18Check")
 
 	# --- Test 1: auth panel starts hidden ---
 	if _check("auth panel starts hidden", not auth_panel.visible):
@@ -58,7 +58,7 @@ func _run() -> void:
 	else:
 		failed += 1
 
-	if _check("DOB field hidden in Login mode", not dob_edit.visible):
+	if _check("Over18 checkbox hidden in Login mode", not over_18_check.visible):
 		passed += 1
 	else:
 		failed += 1
@@ -82,7 +82,7 @@ func _run() -> void:
 	else:
 		failed += 1
 
-	if _check("DOB field visible in Register mode", dob_edit.visible):
+	if _check("Over18 checkbox visible in Register mode", over_18_check.visible):
 		passed += 1
 	else:
 		failed += 1
@@ -101,7 +101,7 @@ func _run() -> void:
 	else:
 		failed += 1
 
-	if _check("DOB field hidden after switching back to Login", not dob_edit.visible):
+	if _check("Over18 checkbox hidden after switching back to Login", not over_18_check.visible):
 		passed += 1
 	else:
 		failed += 1