overlay + library: the preloader working on glass, album names that land on the right self-titled record, and covers warmed before you scroll to them

src/lib/api.js

@@ -140,6 +140,10 @@ export const openExternal = (url) => invoke("open_external", { url });
 // pixels on the long side. Omit it only where true pixels matter (the
 // fullscreen viewer, the import picker's comparison and loupe).
 export const albumArt = (path, maxEdge = null) => invoke("album_art", { path, maxEdge });
+/** Warm the disk thumbnail cache for the whole library at the given edges —
+ * [{warm, decoded}] per edge. Slow by design (one decode at a time); callers
+ * fire-and-forget it. */
+export const libraryArtPrewarm = (edges) => invoke("library_art_prewarm", { edges });
 /** The cover embedded in a streamed track's own cache file, extracted to a
  * local image path — null while the transfer is too young to read, or when
  * the peer's file simply carries no picture. */