android: the downloads say so in the shade

A Save still running with the app in the background now posts a progress
notice — how many files, the one it is on, a bar, Stop all and Open — and
takes it down when the queue empties. It sits on its own low-importance
channel so it can be silenced without silencing the player's card, and
rides its own dataSync foreground service rather than the media one: a
mediaPlayback service stops itself when the bar empties, a download is not
playback, and nothing else was keeping the process alive for a Save with
nothing playing — which is how the first real Save died, four tracks in.
Stop all goes through the same cancel(id) a row's tap takes, and Transfers
grew the matching button beside Clear finished. The walk pushes two rows
straight into the transfer store and reads the real notification back out
of `dumpsys notification`, without fetching anything.

src/lib/api.js

@@ -506,6 +506,10 @@ export const requestAllFilesAccess = () => invoke("plugin:storage|request_all_fi
 // The phone's share plugin (crates/tauri-plugin-share): what another app
 // shared to SoulStream, { text } — read once.
 export const pendingShare = () => invoke("plugin:share|pending_share");
+// The phone's downloads notice (crates/tauri-plugin-transfer-notice): what
+// Save is still fetching, mirrored into the shade; `clear` takes it down.
+export const transferNotice = (state) => invoke("plugin:transfer-notice|update", { state });
+export const clearTransferNotice = () => invoke("plugin:transfer-notice|clear");
 // A photo from the phone (the storage plugin): { path } in the app's cache.
 export const pickImage = () => invoke("plugin:storage|pick_image");
 // Download a found album copy into (Cache)\_audition\<rel>\ for the version