T2 tutorial: all five chapters with Old Tam, scripted dusk and demo wolf, rabbits for the hunt, title-screen Tutorial entry, pause-menu skip/leave, goodbye card; full bot playthrough test

scripts/ui/title_screen.gd

@@ -9,6 +9,8 @@ var _pages: Dictionary = {}     ## name -> Control
 var _name_edit: LineEdit
 var _seed_edit: LineEdit
 var _rot_pick: OptionButton
+## The page to open on (the tutorial's "Start your own world" sends you to "new").
+static var start_page := ""
 ## [setting, what the New World page calls it]
 const ROT_CHOICES := [["normal", "Normally (raw meat lasts 2 days)"], ["slow", "Slowly (twice as long)"], ["off", "Never"]]
 var _list: VBoxContainer
@@ -100,7 +102,8 @@ func _ready() -> void:
 	Net.players_changed.connect(func():
 		if _pages["lobby"].visible:
 			_fill_lobby())
-	_show("main")
+	_show(start_page if start_page in _pages else "main")
+	start_page = ""
 	# Back from a server (left, kicked, or it went away): say why.
 	if Net.state == "offline" and not Net.last_reason.is_empty():
 		_show("join")
@@ -202,9 +205,13 @@ func _main_page() -> Control:
 	var v := VBoxContainer.new()
 	v.add_theme_constant_override("separation", 10)
 	var worlds := Saves.list_worlds()
-	if not worlds.is_empty():
+	if worlds.is_empty():
+		v.add_child(UITheme.label("New here? Try the tutorial (about 20 minutes).", 15, UITheme.TEXT_DIM))
+	else:
 		var w: Dictionary = worlds[0]
 		v.add_child(_button("Continue: %s" % w.name, _play.bind(w.id)))
+	var tut := tutorial_world()
+	v.add_child(_button("Tutorial" if tut.is_empty() else "Tutorial (carry on)", _play_tutorial))
 	v.add_child(_button("New World", _show.bind("new")))
 	var lb := _button("Load World", _show.bind("load"))
 	lb.disabled = worlds.is_empty()
@@ -673,6 +680,20 @@ func _create() -> void:
 	var rot: String = ROT_CHOICES[maxi(_rot_pick.selected, 0)][0]
 	_play(Saves.create_world(world_name, seed, {"rot": rot}))
 
+## The tutorial (docs/TUTORIAL_DESIGN.md): its own world on the original
+## island (seed 1337), made the first time and carried on after that.
+const TUTORIAL_SEED := 1337
+
+static func tutorial_world() -> Dictionary:
+	for w in Saves.list_worlds():
+		if bool(w.get("tutorial", false)):
+			return w
+	return {}
+
+func _play_tutorial() -> void:
+	var w := tutorial_world()
+	_play(String(w.id) if not w.is_empty() else Saves.create_world("Tutorial", TUTORIAL_SEED, {"tutorial": true}))
+
 func _play(id: String) -> void:
 	Saves.current_id = id
 	get_tree().change_scene_to_file(WORLD_SCENE)