feat: display original asset names instead of hashes in assets panel (#9626)

## Problem
Output assets in the assets panel show content hashes (e.g.,
`a1b2c3d4.png`) instead of display names (e.g., `ComfyUI_00001_.png`).

## Root Cause
Cloud inference replaces `filename` with the content hash in the output
transform pipeline. The hashed filename gets stored in the jobs table's
`preview_output` JSONB. The frontend uses this hash as the display name.

## Solution
- Add `display_name` field to `AssetItem` schema and `ResultItemImpl`
- Backend (cloud PR) joins job→assets table to resolve the original name
and injects `display_name` into job responses
- Frontend prefers `display_name` over `name` **only for display text
and download filenames**
- `asset.name` remains unchanged (the hash) for URLs, drag-to-canvas,
export filters, and output key dedup

## Backwards Compatible
- OSS: `display_name` is undefined, falls back to `asset.name` (which is
already the real filename in OSS)
- Cloud pre-deploy: `display_name` absent from API, falls back
gracefully
- Old jobs with no assets: `display_name` not injected, no change

## Cloud PR
https://github.com/Comfy-Org/cloud/pull/2747



https://github.com/user-attachments/assets/8a4c9cac-4ade-4ea2-9a70-9af240a56602

src/components/sidebar/tabs/AssetsSidebarTab.vue

@@ -569,7 +569,7 @@ const handleZoomClick = (asset: AssetItem) => {
     const dialogStore = useDialogStore()
     dialogStore.showDialog({
       key: 'asset-3d-viewer',
-      title: asset.name,
+      title: asset.display_name || asset.name,
       component: Load3dViewerContent,
       props: {
         modelUrl: asset.preview_url || ''