fix(scripts): prevent duplicate script attachment per entity

The per-entity script list allowed picking the same script class
twice; the name-keyed runtime silently ignores duplicates, leaving
the extra rows dead weight with unusable enable bits. Enforce
DisallowMultipleComponent semantics: the dropdown of each row only
offers unattached names (own name kept for echo), "+ Add Script"
disables when every registered script is attached, and scene loading
dedupes as a safety net for hand-edited files.

App/editor/InspectorPanel.cpp

@@ -569,23 +569,41 @@ void InspectorPanel::Draw(const EditorContext& ctx, entt::entity selected)
             // 多脚本列表（Unity 语义）：每行 = 脚本下拉 + 独立启停 + 删除；
             // 实例生命周期由 ScriptRuntime 对账（删行/改名 → 下帧 OnDestroy）
             const auto& names = Engine::Scripting::ScriptRegistry::Names();
-            std::vector<const char*> options;
-            options.push_back("<none>");
-            for (const auto& n : names)
-            {
-                options.push_back(n.c_str());
-            }
             int removeIdx = -1;
             for (int i = 0; i < static_cast<int>(sc->items.size()); ++i)
             {
                 auto& item = sc->items[static_cast<size_t>(i)];
                 ImGui::PushID(i);
+                // 去重下拉（DisallowMultipleComponent 语义）：可选项 =
+                // "<none>" + 未挂名 + 自身名（已挂的别人的名不出现，结构上
+                // 选不出重复）；自身名置于末尾保证已挂项正常回显
+                std::vector<const char*> options;
+                options.push_back("<none>");
+                for (const auto& n : names)
+                {
+                    if (n == item.name)
+                    {
+                        continue;
+                    }
+                    const bool attached = std::any_of(
+                        sc->items.begin(), sc->items.end(),
+                        [&](const Engine::ECS::ScriptComponent::Item& it)
+                        { return it.name == n; });
+                    if (!attached)
+                    {
+                        options.push_back(n.c_str());
+                    }
+                }
+                if (!item.name.empty())
+                {
+                    options.push_back(item.name.c_str());
+                }
                 int cur = 0;
-                for (size_t k = 0; k < names.size(); ++k)
+                for (size_t k = 0; k < options.size(); ++k)
                 {
-                    if (names[k] == item.name)
+                    if (item.name == options[k])
                     {
-                        cur = static_cast<int>(k) + 1;
+                        cur = static_cast<int>(k);
                     }
                 }
                 ImGui::SetNextItemWidth(
@@ -593,7 +611,7 @@ void InspectorPanel::Draw(const EditorContext& ctx, entt::entity selected)
                 if (ImGui::Combo("##script", &cur, options.data(),
                                  static_cast<int>(options.size())))
                 {
-                    item.name = (cur <= 0) ? "" : names[static_cast<size_t>(cur) - 1];
+                    item.name = (cur <= 0) ? "" : options[static_cast<size_t>(cur)];
                 }
                 ImGui::SameLine();
                 ImGui::Checkbox("##en", &item.active);
@@ -615,7 +633,25 @@ void InspectorPanel::Draw(const EditorContext& ctx, entt::entity selected)
             {
                 sc->items.erase(sc->items.begin() + removeIdx);
             }
-            if (ImGui::Button("+ Add Script"))
+            // 已注册脚本全部挂上 → 禁止再加（去重语义，无意义项）
+            const bool allAttached = !names.empty() &&
+                std::all_of(names.begin(), names.end(),
+                    [&](const std::string& n)
+                    {
+                        return std::any_of(
+                            sc->items.begin(), sc->items.end(),
+                            [&](const Engine::ECS::ScriptComponent::Item& it)
+                            { return it.name == n; });
+                    });
+            if (allAttached)
+            {
+                ImGui::BeginDisabled(true);
+                ImGui::Button("+ Add Script");
+                ImGui::EndDisabled();
+                ImGui::SameLine();
+                ImGui::TextDisabled("all registered scripts attached");
+            }
+            else if (ImGui::Button("+ Add Script"))
             {
                 sc->items.push_back({});
             }

Engine/src/Serialization/SceneSerializer.cpp

@@ -28,6 +28,7 @@
 #include <glm/glm.hpp>
 #include <glm/gtc/quaternion.hpp>
 
+#include <algorithm>
 #include <cmath>
 #include <filesystem>
 #include <fstream>
@@ -672,8 +673,17 @@ namespace Engine::Serialization {
                         ECS::ScriptComponent::Item item;
                         item.name = it["Name"].as<std::string>("");
                         item.active = it["Active"].as<bool>(true);
+                        // 去重兜底：同名项只收第一份（UI 已杜绝重复，
+                        // 手编场景仍可能写出重复）
+                        const bool dup = std::any_of(
+                            sc.items.begin(), sc.items.end(),
+                            [&](const ECS::ScriptComponent::Item& e) {
+                                return e.name == item.name;
+                            });
+                        if (!dup) {
                             sc.items.push_back(std::move(item));
                         }
+                    }
                 } else {
                     // 旧格式：Script: {ScriptName: ..., Active: ...}
                     ECS::ScriptComponent::Item item;