feat(mana): PlayerStats 蓝池状态 + spend/regen/set_pool + reset 置满

scripts/autoloads/player_stats.gd

@@ -22,6 +22,11 @@ var cpu_limit:     int = 5    # 控制 MAX_OPS = cpu_limit * 40
 var armor:         float = 0.0
 var resistance:    float = 0.0  # 0.0~1.0
 
+# ── 魔力（MVP）─────────────────────────────────────────
+var mana:       float = 100.0
+var mana_max:   float = 100.0
+var mana_regen: float = 5.0    # 每秒回复
+
 func _ready() -> void:
 	EventBus.subscribe(EventID.PLAYER_DAMAGED, _on_player_damaged)
 
@@ -64,11 +69,34 @@ func heal(amount: float) -> void:
 func get_hp_percent() -> float:
 	return hp / max(hp_max, 0.001)
 
+## 换杖时设定蓝池上限/回速，并把当前蓝夹到 [0, max]
+func set_mana_pool(max_v: float, regen: float) -> void:
+	mana_max   = max_v
+	mana_regen = regen
+	mana       = clampf(mana, 0.0, mana_max)
+	stats_changed.emit()
+
+## 花费魔力；够则扣除返回 true，否则不变返回 false
+func spend_mana(cost: float) -> bool:
+	if mana < cost:
+		return false
+	mana -= cost
+	stats_changed.emit()
+	return true
+
+## 每帧回蓝（PlayerManager 驱动）。不 emit stats_changed —— HUD 每帧直接读 mana，
+## 避免回蓝过程每帧发信号触发商店刷新。
+func regen_mana(delta: float) -> void:
+	if mana >= mana_max:
+		return
+	mana = min(mana_max, mana + mana_regen * delta)
+
 func _on_player_damaged(payload: Dictionary) -> void:
 	take_damage(float(payload.get("damage", 0.0)))
 
 func reset_for_run() -> void:
 	hp        = hp_max
+	mana      = mana_max
 	gold      = 0
 	xp        = 0
 	level     = 1