refactor: centralize display_name || name into getAssetDisplayName (#9641)

## Summary

Centralize the inline `display_name || name` pattern into
`getAssetDisplayName`, adding `display_name` to the existing metadata
fallback chain.

## Changes

- **What**: Update `getAssetDisplayName` fallback chain to
`user_metadata.name → metadata.name → display_name → name`. Replace all
6 inline `asset.display_name || asset.name` call sites with the shared
utility. Remove duplicate local function in `AssetsSidebarListView.vue`.

## Review Focus

The fallback order preserves user_metadata overrides while incorporating
the `display_name` field added in #9626. All callers now go through a
single code path.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9641-refactor-centralize-display_name-name-into-getAssetDisplayName-31e6d73d365081e09e5de85486583443)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: GitHub Action <action@github.com>

src/components/sidebar/tabs/AssetsSidebarListView.vue

@@ -90,6 +90,7 @@ import AssetsListItem from '@/platform/assets/components/AssetsListItem.vue'
 import type { OutputStackListItem } from '@/platform/assets/composables/useOutputStacks'
 import { getOutputAssetMetadata } from '@/platform/assets/schemas/assetMetadataSchema'
 import type { AssetItem } from '@/platform/assets/schemas/assetSchema'
+import { getAssetDisplayName } from '@/platform/assets/utils/assetMetadataUtils'
 import { iconForMediaType } from '@/platform/assets/utils/mediaIconUtil'
 import { useAssetsStore } from '@/stores/assetsStore'
 import {
@@ -135,10 +136,6 @@ const listGridStyle = {
   gap: '0.5rem'
 }
 
-function getAssetDisplayName(asset: AssetItem): string {
-  return asset.display_name || asset.name
-}
-
 function getAssetPrimaryText(asset: AssetItem): string {
   return truncateFilename(getAssetDisplayName(asset))
 }