fix: support text and misc generated asset states (#8914)

## Summary
Align generated-asset state classification to a single shared source and
implement the missing text/misc states in both card and list previews.

## Changes
- **What**:
- Extended `getMediaTypeFromFilename` in
`packages/shared-frontend-utils` to return `text` and `other`, and
changed unknown/no-extension fallback from `image` to `other`.
- Added text extension handling (`txt`, `md`, `json`, `csv`, `yaml/yml`,
`xml`, `log`) and kept existing media kinds.
- Updated generated-assets UI to use shared media-type detection
directly (removed the local generated-assets classifier).
  - Added text and misc card preview components:
    - `text` -> `icon-[lucide--text]`
    - `other` -> `icon-[lucide--check-check]`
- Updated list-item preview behavior so only `image`/`video` use preview
media URLs; `text`/`other` use icon fallback.
- Widened media kind schema for asset display metadata to include `text`
and `other`.
- **Breaking**: No API breaking changes; internal media kind union
widened for frontend asset display paths.
- **Dependencies**: None.

## Review Focus
- Verify generated text assets render paragraph/text icon state in card
+ list.
- Verify unknown/misc assets consistently render double-check icon state
in card + list.
- Verify existing image/video/audio/3D behavior remains unchanged.

## Screenshots (if applicable)
<img width="282" height="158" alt="image"
src="https://github.com/user-attachments/assets/76cf2d1b-9d34-4c7c-92a1-50bbc55871e5"
/>
<img width="432" height="489" alt="image"
src="https://github.com/user-attachments/assets/024fece3-f241-484d-a37e-11948559ebbc"
/>
<img width="421" height="494" alt="image"
src="https://github.com/user-attachments/assets/ed64ba0c-bf46-4c3b-996e-4bc613ee029e"
/>


┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8914-fix-support-text-and-misc-generated-asset-states-3096d73d365081f28ca7c32f306e4b50)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Johnpaul Chiwetelu <49923152+Myestery@users.noreply.github.com>
Co-authored-by: GitHub Action <action@github.com>

src/components/sidebar/tabs/AssetsSidebarListView.vue

@@ -43,7 +43,7 @@
                 item.isChild && 'pl-6'
               )
             "
-            :preview-url="item.asset.preview_url"
+            :preview-url="getAssetPreviewUrl(item.asset)"
             :preview-alt="item.asset.name"
             :icon-name="iconForMediaType(getAssetMediaType(item.asset))"
             :is-video-preview="isVideoAsset(item.asset)"
@@ -142,6 +142,14 @@ function isVideoAsset(asset: AssetItem): boolean {
   return getAssetMediaType(asset) === 'video'
 }
 
+function getAssetPreviewUrl(asset: AssetItem): string {
+  const mediaType = getAssetMediaType(asset)
+  if (mediaType === 'image' || mediaType === 'video') {
+    return asset.preview_url || ''
+  }
+  return ''
+}
+
 function getAssetSecondaryText(asset: AssetItem): string {
   const metadata = getOutputAssetMetadata(asset.user_metadata)
   if (typeof metadata?.executionTimeInSeconds === 'number') {