editor camera: dedicated Scene-view camera decoupled from camera entities

EditorCamera (UE FEditorViewportClient semantics) owned by SceneRenderer:
own TransformComponent + reused Camera controller. BuildFrame dispatches
render source by display mode — editor form always renders from the
editor camera (usable in empty scenes), game form renders from the
scene's primary camera entity. AlignTo copies an entity pose into the
editor camera ("Align Viewport to Camera" button in Inspector). F focus
and viewport gizmo now follow the same dispatch. main.cpp stripped of
dangling sandbox camera/spinner state; onSceneLoaded hook removed.

App/editor/InspectorPanel.cpp

@@ -198,7 +198,7 @@ void InspectorPanel::Draw(const EditorContext& ctx, entt::entity selected)
             if (ImGui::Checkbox("primary", &cam->primary) && cam->primary)
             {
                 // primary 互斥：启用本相机时清掉其余实体的 primary
-                //（引擎取第一个 primary 作为渲染视角）
+                //（引擎取第一个 primary 作为游戏形态渲染视角）
                 reg.view<Engine::ECS::CameraComponent>().each(
                     [&](entt::entity e, Engine::ECS::CameraComponent& c)
                     {
@@ -208,6 +208,18 @@ void InspectorPanel::Draw(const EditorContext& ctx, entt::entity selected)
                         }
                     });
             }
+
+            // 对齐跳转：把本实体位姿复制给编辑器相机，Scene view 立即
+            // 从该位置观看（只取位姿，不接管渲染——渲染源分派在
+            // SceneRenderer，编辑器形态恒用编辑器相机）
+            if (ImGui::Button("Align Viewport to Camera") && ctx.editorCamera)
+            {
+                if (auto* tr = reg.try_get<Engine::ECS::TransformComponent>(
+                        selected))
+                {
+                    ctx.editorCamera->AlignTo(*tr);
+                }
+            }
         }
     }