feat: HUD 增加时间流速控制，新增 Settings 持久化

- 顶栏改为暂停/1x/5x/20x 按钮组，当前档位高亮
- TimeSystem 支持暂停与档位切换
- 新增 Settings 单例，存档默认流速并开机应用
- GameState 补充年月日，支持 12x30 历法推进

src/Core/GameState.gd

@@ -5,9 +5,17 @@ enum GameMode { NEW_GAME, LOAD_GAME }
 var mode: GameMode = GameMode.NEW_GAME
 var save_id: String = ""
 
+# 游戏内时间（12 月 × 30 天 = 360 天/年）
+var year: int = 1
+var month: int = 1
+var day: int = 1
+
 func request_new_game() -> void:
 	mode = GameMode.NEW_GAME
 	save_id = ""
+	year = 1
+	month = 1
+	day = 1
 
 func request_load_game(id: String) -> void:
 	mode = GameMode.LOAD_GAME

src/Core/MainGame.gd

@@ -1,6 +1,8 @@
 extends Node
 
 func _ready() -> void:
+	TimeSystem.speed_index = Settings.default_speed_index
+	TimeSystem.speed = TimeSystem.SPEEDS[TimeSystem.speed_index]
 	pass
 
 

src/Core/Settings.gd

@@ -0,0 +1,14 @@
+extends Node
+
+const SAVE_PATH := "user://settings.cfg"
+var default_speed_index := 1   # 默认 5x
+
+func load_settings() -> void:
+	var cfg := ConfigFile.new()
+	if cfg.load(SAVE_PATH) == OK:
+		default_speed_index = cfg.get_value("time", "speed_index", 1)
+
+func save_settings() -> void:
+	var cfg := ConfigFile.new()
+	cfg.set_value("time", "speed_index", default_speed_index)
+	cfg.save(SAVE_PATH)

src/Core/Settings.gd.uid

@@ -0,0 +1 @@
+uid://exwk46qy4x6t

src/Core/TimeSystem.gd

@@ -2,11 +2,17 @@ extends Node
 
 signal day_passed(year, month, day)
 
+const SPEEDS := [1.0, 5.0, 20.0]
+var speed_index := 0
+
 const DAY_LENGTH := 5.0
 var speed := 1.0
+var paused := false
 var _elapsed := 0.0
 
 func _process(delta: float) -> void:
+	if paused:
+		return
 	_elapsed += delta * speed
 	if _elapsed >= DAY_LENGTH:
 		_elapsed -= DAY_LENGTH
@@ -16,3 +22,19 @@ func _advance() -> void:
 	# GameState.year, GameState.month, GameState.day 推进
 	GameState.day = GameState.day + 1;
 	day_passed.emit()
+
+func cycle_speed() -> float:
+	speed_index = (speed_index + 1) % SPEEDS.size()
+	speed = SPEEDS[speed_index]
+	return speed
+
+func set_speed_index(index: int) -> void:
+	speed_index = clampi(index, 0, SPEEDS.size() - 1)
+	speed = SPEEDS[speed_index]
+
+func toggle_pause() -> bool:
+	paused = not paused
+	return paused
+
+func get_speed_label() -> String:
+	return "x%d" % int(speed)