support panoramic image in 3d node (#6638)

## Summary

Adds panoramic image support to the 3D node viewer, allowing users to
display equirectangular panoramic images as immersive backgrounds
alongside the existing tiled image mode.

## Changes

- Toggle between tiled and panorama rendering modes for background
images
- Field of view (FOV) control for panorama mode
- Refactored FOV slider into reusable PopupSlider component

## Screenshots


https://github.com/user-attachments/assets/8955d74b-b0e6-4b26-83ca-ccf902b43aa6

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6638-support-panoramic-image-in-3d-node-2a56d73d365081b98647f988130e312e)
by [Unito](https://www.unito.io)

src/components/load3d/Load3DControls.vue

@@ -39,6 +39,8 @@
         v-model:show-grid="sceneConfig!.showGrid"
         v-model:background-color="sceneConfig!.backgroundColor"
         v-model:background-image="sceneConfig!.backgroundImage"
+        v-model:background-render-mode="sceneConfig!.backgroundRenderMode"
+        v-model:fov="cameraConfig!.fov"
         @update-background-image="handleBackgroundImageUpdate"
       />