## Description
Wholphin builds item image URLs without Jellyfin's `tag` query
parameter. `ImageUrlService` already receives the item's `imageTags` and
`backdropTags`, and the low-level `getItemImageUrl` supports `tag`, but
no branch passed it. Today only chapter and now-playing images set it.
Before: `/Items/{id}/Images/Primary?quality=96&fillHeight=229`
After:
`/Items/{id}/Images/Primary?quality=96&fillHeight=229&tag={ImageTags.Primary}`
This is how the official Jellyfin clients request images. jellyfin-web
and the official Jellyfin Android TV app both copy `ImageTags[...]` (and
the parent/series tags) into the image URL.
I also added `ImageUrlServiceTest`, which covers each branch.
### Related issues
I tested each one on the emulator against a stock Jellyfin 12.1 server
(no plugins), comparing `main` with this branch:
- **#366 (Image cache expiration): fixed by this PR.**
- **#1249 (blank tile for a newly added movie) and #1338 (episode cover
never refreshes): already fixed on `main` since v1.0.3, not by this
PR.**
- **#360 (Option to hide spoilers): partly.**
## AI or LLM usage
This change was made with AI assistance (Claude Code). It was used for:
- the code changes in `ImageUrlService` and the call sites listed above
- the new `ImageUrlServiceTest`
- the emulator testing and benchmarks
- drafting this description
The testing is what's described above: unit tests, an Android TV
emulator against Jellyfin 12.1 servers (with Jellyfin Enhanced and
stock), request logs from a proxy, and a check of every tag against the
server's metadata. I've reviewed the change and can explain it.
I'm also a maintainer on Jellyfin Enhanced, which is how I ran into
this. I'm happy to share examples of my own coding work if that helps
with reviewing this.
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