feat(resist): 设计器敌人页增元素抗性网格(6×5) + _save 写 resistances（全0省略）

主表下方加 6原型×5元素(火/冰/雷/毒/奥) SpinBox 网格(-0.9~0.9)；_save 汇总
非零抗性写入 resistances，全0则省略键。读写往返 MCP 实测 FAILS=0
（读种子 fire0.5/ice-0.5，写非零、零值省略、负值保留）。

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

addons/game_designer/enemy_tab.gd

@@ -5,6 +5,8 @@ extends VBoxContainer
 const UI = preload("res://addons/game_designer/designer_ui.gd")
 const PATH = "res://data/enemies.json"
 const NAMES = ["杂兵 Basic", "快速 Fast", "护甲 Armored", "精英 Elite", "首领 MiniBoss", "终焉 Boss"]
+const ELEM_KEYS   = ["fire", "ice", "lightning", "poison", "arcane"]
+const ELEM_LABELS = ["火 Fire", "冰 Ice", "雷 Lightning", "毒 Poison", "奥 Arcane"]
 
 var _data: Dictionary = {}
 var _rows: Array = []   # [{speed:SpinBox, armor:SpinBox, size:SpinBox, color:ColorPickerButton}]
@@ -35,6 +37,26 @@ func _ready() -> void:
 		grid.add_child(sp); grid.add_child(ar); grid.add_child(sz); grid.add_child(cp)
 		_rows.append({"speed": sp, "armor": ar, "size": sz, "color": cp})
 	add_child(HSeparator.new())
+	add_child(UI.cell_label("元素抗性 Resistances（-0.9~0.9，负=弱点加伤）"))
+	var rgrid := GridContainer.new()
+	rgrid.columns = ELEM_KEYS.size() + 1
+	add_child(rgrid)
+	var rhead := Label.new(); rhead.text = "原型"; rhead.modulate = Color(0.7, 0.8, 1.0)
+	rgrid.add_child(rhead)
+	for el in ELEM_LABELS:
+		var el_l := Label.new(); el_l.text = el; el_l.modulate = Color(0.7, 0.8, 1.0)
+		rgrid.add_child(el_l)
+	for i in 6:
+		var d2: Dictionary = _data.get(str(i), {})
+		var res_d: Dictionary = d2.get("resistances", {})
+		rgrid.add_child(UI.cell_label(NAMES[i]))
+		var res_spins := {}
+		for ei in ELEM_KEYS.size():
+			var ename: String = ELEM_KEYS[ei]
+			var sp2 := UI.spin(-0.9, 0.9, 0.05, float(res_d.get(ename, 0.0)))
+			rgrid.add_child(sp2)
+			res_spins[ename] = sp2
+		_rows[i]["resist"] = res_spins
 	add_child(UI.btn("💾 保存 enemies.json", _save))
 	_status = UI.status_label()
 	add_child(_status)
@@ -47,13 +69,21 @@ func _save() -> void:
 	var out: Dictionary = {}
 	for i in 6:
 		var r: Dictionary = _rows[i]
-		out[str(i)] = {
+		var entry := {
 			"name": NAMES[i],
 			"speed": r["speed"].value,
 			"armor": r["armor"].value,
 			"size": r["size"].value,
 			"color": [r["color"].color.r, r["color"].color.g, r["color"].color.b],
 		}
+		var rd := {}
+		for ename in ELEM_KEYS:
+			var v: float = r["resist"][ename].value
+			if absf(v) > 0.0001:
+				rd[ename] = v
+		if not rd.is_empty():
+			entry["resistances"] = rd
+		out[str(i)] = entry
 	if UI.save_json(PATH, out):
 		UI.set_status(_status, "💾 已保存（重启游戏 F5 生效）")
 	else: