Reorganize directory layout: editor panels/, grouped shaders, drop stale header

- App/editor: move 7 panels into panels/ (Editor core stays at root)
- shaders/: group into pbr/ post/ debug/ env/ (runtime load paths updated)
- Delete outdated duplicate Engine/src/Renderer/VulkanAssetUploader.h

shaders/debug/gizmo_pick.frag

@@ -0,0 +1,12 @@
+#version 450
+
+// Editor gizmo 拾取片元：实体 id 原样写 R32Uint（与 hitproxy.frag 同
+// 语义）。flat = 无插值，像素值即命中图元的实体位模式。
+
+layout(location = 0) flat in uint inEntityId;
+
+layout(location = 0) out uvec4 outColor;
+
+void main() {
+    outColor = uvec4(inEntityId, 0u, 0u, 0u);
+}