feat(mana): 游戏设计器支持 mana 字段（补 Mana MVP 配套）

- Core 编辑器加「蓝上限/回蓝」两栏（_on_select 读 / _on_apply 写 / _on_new 默认），
  修复此前编辑 Core 保存会静默丢失 mana_max/mana_regen 的数据丢失洞
- 法术编辑器 4 个 meta 模板加 mana_cost，新法术默认有合理蓝耗
- handbook 07 补 Core 蓝池字段 + 法术 mana_cost 说明

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

addons/game_designer/core_tab.gd

@@ -16,6 +16,8 @@ var _slots: SpinBox
 var _topo: OptionButton
 var _cpu: SpinBox
 var _interval: SpinBox
+var _mana_max: SpinBox
+var _mana_regen: SpinBox
 var _feat: OptionButton
 var _rows: SpinBox
 var _cols: SpinBox
@@ -39,6 +41,8 @@ func _ready() -> void:
 	_topo = _row("拓扑", UI.opt(TOPO, 0))
 	_cpu = _row("CPU 上限", UI.spin(1, 40, 1, 5))
 	_interval = _row("施法间隔(s)", UI.spin(0.05, 5, 0.05, 0.5))
+	_mana_max = _row("蓝上限(Mana Max)", UI.spin(0, 1000, 5, 100))
+	_mana_regen = _row("回蓝/秒(Mana Regen)", UI.spin(0, 100, 0.5, 5))
 	_feat = _row("特性", UI.opt(FEAT, 0))
 	_rows = _row("矩阵行(MATRIX)", UI.spin(1, 8, 1, 1))
 	_cols = _row("矩阵列(MATRIX)", UI.spin(1, 16, 1, 5))
@@ -81,6 +85,8 @@ func _on_select(idx: int) -> void:
 	_topo.selected = int(d.get("topology", 0))
 	_cpu.value = float(d.get("cpu_limit", 5))
 	_interval.value = float(d.get("cast_interval", 0.5))
+	_mana_max.value = float(d.get("mana_max", 100))
+	_mana_regen.value = float(d.get("mana_regen", 5))
 	_feat.selected = int(d.get("feature_tags", 0))
 	_rows.value = float(d.get("grid_rows", 1))
 	_cols.value = float(d.get("grid_cols", 5))
@@ -99,6 +105,7 @@ func _on_apply() -> void:
 		"display_name": _name.text, "slot_count": int(_slots.value),
 		"topology": _topo.selected, "cpu_limit": int(_cpu.value),
 		"cast_interval": _interval.value, "feature_tags": _feat.selected,
+		"mana_max": int(_mana_max.value), "mana_regen": _mana_regen.value,
 		"grid_rows": int(_rows.value), "grid_cols": int(_cols.value), "edges": edges,
 	}
 	_cur = cid
@@ -110,7 +117,8 @@ func _on_new() -> void:
 	var i := 1
 	while _data.has(cid): cid = "new_core_%d" % i; i += 1
 	_data[cid] = {"display_name": cid, "slot_count": 5, "topology": 0,
-		"cpu_limit": 5, "cast_interval": 0.5, "feature_tags": 0, "edges": []}
+		"cpu_limit": 5, "cast_interval": 0.5, "feature_tags": 0,
+		"mana_max": 100, "mana_regen": 5, "edges": []}
 	_refresh()
 
 func _on_delete() -> void: