feat(title): TitleScreen composition, menu + selection, boot scene

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

client/tests/unit/test_title_screen.gd

@@ -0,0 +1,52 @@
+extends "res://addons/gut/test.gd"
+
+const SCENE := "res://scenes/title/TitleScreen.tscn"
+
+
+func _title() -> TitleScreen:
+	var t = load(SCENE).instantiate()
+	add_child_autofree(t)  # runs _ready()
+	return t
+
+
+func _index_of(t: TitleScreen, action: StringName) -> int:
+	for i in range(t._rows.size()):
+		if t._rows[i].get_meta("action") == action:
+			return i
+	return -1
+
+
+func test_six_menu_rows_each_with_an_action():
+	var t := _title()
+	assert_eq(t._rows.size(), 6)
+	for row in t._rows:
+		assert_true(row.has_meta("action"))
+
+
+func test_down_moves_selection():
+	var t := _title()
+	assert_eq(t._sel, 0)
+	t._move(1)
+	assert_eq(t._sel, 1)
+
+
+func test_up_from_first_wraps_to_last():
+	var t := _title()
+	t._move(-1)
+	assert_eq(t._sel, t._rows.size() - 1)
+
+
+func test_new_game_and_quit_emit_their_action():
+	var t := _title()
+	# Isolate the signal seam so the test does not actually change scene / quit.
+	t.menu_activated.disconnect(t._on_menu_activated)
+	watch_signals(t)
+	t._activate(_index_of(t, &"new_game"))
+	assert_signal_emitted_with_parameters(t, "menu_activated", [&"new_game"])
+	t._activate(_index_of(t, &"quit"))
+	assert_signal_emitted_with_parameters(t, "menu_activated", [&"quit"])
+
+
+func test_footer_shows_version():
+	var t := _title()
+	assert_string_contains(t._footer_left.text, Version.new().string())