feat: 多光源——点光源类型（距离衰减，位置来自 Transform）

- LightComponent 加 Type（Directional/Point）+ radius；点光位置取
  实体 Transform（固有组件首次实际受益）
- LightData shader 契约扩为 4×vec4（color/direction/position/params，
  每灯 64B，未用字段置零）；UBO 688→816B
- 光照循环按类型分支：方向光无衰减；点光 L 指向光源 + 平方距离衰减，
  衰减半径外跳过；CSM 阴影只来自第 0 盏方向光
- main.cpp：SunTemple 场景加暖橙火坑光 + 冷蓝填充光（点光）；
  KeyLight/FillLight 改 designated initializer

Engine/src/Renderer/SceneRenderer.cpp

@@ -168,24 +168,39 @@ namespace Engine
 
         ubo.ambientColor = scene.GetSettings().ambientColor;
 
-        // ---- 2. 灯光（第一个灯作为阴影光源）----
+        // ---- 2. 灯光（第一个方向光作为 CSM 阴影光源；点光位置来自 Transform）----
         u32 lightCount = 0;
         glm::vec3 shadowDir{0.0f, -1.0f, 0.0f};   // 无灯兜底：头顶正射
-        scene.Each<LightComponent>([&](Entity, LightComponent& light) {
+        scene.Each<TransformComponent, LightComponent>(
+            [&](Entity, TransformComponent& t, LightComponent& light) {
             if (lightCount >= kMaxLights) return;
 
-            glm::vec3 dir = glm::length(light.direction) > 0.0f
-                ? glm::normalize(light.direction)
-                : glm::vec3(0.0f);
-            ubo.lights[lightCount].direction = glm::vec4(dir, 0.0f);
-            ubo.lights[lightCount].color = light.color;
+            auto& dst = ubo.lights[lightCount];
+            dst.color = light.color;
+            dst.params = glm::vec4(
+                light.type == LightComponent::Type::Point ? 1.0f : 0.0f,
+                light.radius, 0.0f, 0.0f);
 
-            if (lightCount == 0) shadowDir = dir;
+            if (light.type == LightComponent::Type::Point) {
+                dst.position = glm::vec4(t.GetPosition(), 1.0f);
+                dst.direction = glm::vec4(0.0f);
+            } else {
+                glm::vec3 dir = glm::length(light.direction) > 0.0f
+                    ? glm::normalize(light.direction) : glm::vec3(0.0f);
+                dst.direction = glm::vec4(dir, 0.0f);
+                dst.position = glm::vec4(0.0f);
+            }
+
+            // CSM 阴影光源 = 第一个方向光（点光不做级联阴影）
+            if (lightCount == 0 &&
+                light.type == LightComponent::Type::Directional) {
+                shadowDir = glm::length(light.direction) > 0.0f
+                    ? glm::normalize(light.direction) : shadowDir;
+            }
             ++lightCount;
         });
         for (u32 i = lightCount; i < kMaxLights; ++i) {
-            ubo.lights[i].direction = glm::vec4(0.0f);
-            ubo.lights[i].color = glm::vec4(0.0f);
+            ubo.lights[i] = {};
         }
         ComputeCascades(shadowDir);
         ubo.cameraPos = glm::vec4(camTransform->GetPosition(), 1.0f);