Feat/search improvements (#470)

* feat(covers): race sibling downscale vs fetch, search thumb priorities

Run getCoverArt and client downscale in parallel when another size of the
same cover is cached; first successful result wins and aborts the other path.
Await both branches so inflight bookkeeping does not detach early.

Extend the cover cache size roster so provisional siblings resolve for sizes
used in the UI (e.g. 400/600/800, 48/96).

CachedImage: fetchQueueBias for live/mobile search (artist thumbnails ahead of
albums in fetch-slot ordering); configurable observeRootMargin with a wider
default to prepare priority slightly before elements enter view.

Mobile search adds round artist-thumb styling; add shared cover blob downscale
helper.

* perf(image-cache): batch sibling IDB reads and guard cover size registry

Use one read transaction when probing IndexedDB for sibling cover keys.
Extract COVER_ART_REGISTERED_SIZES and add Vitest coverage so every literal
coverArtCacheKey(_, size) in src stays aligned with sibling invalidation.
Honor AbortSignal during JPEG encode in downscaleCoverBlob.

CHANGELOG.md

@@ -41,6 +41,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Filter state is ephemeral per page (not persisted) so users don't come back to a half-empty library and wonder where their content went.
 * Reads star state live from in-memory overrides — toggling a favourite from a context menu updates the visible list immediately, no refetch.
 
+### Search — artist photos in live and mobile results
+
+**By [@cucadmuh](https://github.com/cucadmuh), PR [#470](https://github.com/Psychotoxical/psysonic/pull/470)**
+
+* **Live search** and the **mobile search overlay** now load **artist images** for rows in the **Artists** section via the same **`getCoverArt` / image-cache path** as album art (**`coverArt`** when present, otherwise the **artist id** where the server supports it), with a **fallback icon** when art is missing or fails.
+* **Mobile** artist hits use a **round** thumbnail next to **square** album art so the two result types read clearly at a glance.
+
 ## Changed
 
 ### Dependencies — npm / Cargo refresh and rodio 0.22
@@ -66,6 +73,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * **Virtualised lists:** **Albums**, **Artists** (list mode), and the **Tracks** virtual song browser **derive** **TanStack Virtual `overscan`** from the **measured scroll viewport** (~ **one screen** of extra rows above and below) instead of a tiny fixed cushion.
 * **Library & chrome:** assorted **scroll / layout** improvements on **Artist detail**, **Playlists**, **Most played**; smaller touch-ups to **Mini player**, **Live search**, **Album header**, and **dynamic colour** extraction used by player / album surfaces.
 
+### Covers / image cache — parallel fetch + downscale, registry guard, search slot hints
+
+**By [@cucadmuh](https://github.com/cucadmuh), PR [#470](https://github.com/Psychotoxical/psysonic/pull/470)**
+
+* When a **pixel size** misses **disk** but **another size** of the same **`cover:id` is already cached**, **remote `getCoverArt`** and **client JPEG downscale** run in **parallel**; the **first good blob wins** and the other side **aborts** (network + downscale **signals**).
+* **Sibling key reads** use **one IndexedDB readonly transaction** instead of many separate transactions.
+* **`COVER_ART_REGISTERED_SIZES`** centralises known **`getCoverArt` widths** for **invalidation** and sibling lookup; **`coverArtRegisteredSizes.test.ts`** (**Vitest**) keeps **literal** `coverArtCacheKey(_, n)` call sites in **`src`** in sync with that list.
+* **`downscaleCoverBlob`** respects **AbortSignal** through **`canvas.toBlob`**.
+* **`CachedImage`:** **`fetchQueueBias`** gives **artist** search thumbs **higher network-slot priority** than **album** thumbs when the pool is saturated; **`observeRootMargin`** defaults **wider** so **priority** updates **earlier** ahead of the scroll viewport.
+
 ## Fixed
 
 ### Hot cache, HTTP streaming replay, and queue source indicator