android: downloads on Wi-Fi only

One switch the desktop never needed, off by default: on mobile data every
Save the phone can start — a record, a track, a folder, a file, a
playlist's bulk, the now-playing Save — waits, with the reason on the bar;
streaming is never held back. The walk flips the switch, makes the
connection cellular and sees a download refused.

ANDROID.md

@@ -215,7 +215,11 @@ record the queue holds. A moment after boot the phone warms the library's thumbn
 desktop's way (`library_art_prewarm` at the cards' edge, one decode at a
 time behind the tiles' gate). The network results carry the hub's filters (a free slot only; FLAC or
 MP3 320+), and the lyrics sheet has the desktop's paste door (plain text,
-or LRC with timestamps, kept for the track). The nav wears two badges the desktop's chrome has: transfers in flight on
+or LRC with timestamps, kept for the track). One switch the desktop never needed: You → Downloads → "Downloads on
+Wi-Fi only" (`network.svelte.js`, off by default) holds every Save — a
+record, a track, a folder, a file, a playlist's bulk, the now-playing
+Save — while the phone is on mobile data (`navigator.connection.type`);
+streaming is never held back. The nav wears two badges the desktop's chrome has: transfers in flight on
 You (the title bar's download ring) and unread chats on Community.
 The Library's count line carries the collection's hours and the sort
 offers By format (lossless by depth and rate first, then by bitrate); the