Backport from the iOS version: offline downloads, home-first reconnect, stall warning, Close

- Downloads for offline listening: long-press a track, album, artist or
  playlist -> Download; Menu -> Downloads lists them (progress, space used/free,
  play/shuffle, retry, remove). Saved on the SD card (Android/data/com.minamp/
  files/downloads). MP3 originals kept as they are unless above a lower
  download quality; the rest transcoded to MP3 (320 kbps by default). One at a
  time, Range resume for originals, retried when the server is back, Wi-Fi lock.
- Downloaded tracks play from the SD card, offline too; plays made offline
  are reported to Plex when a connection works again.
- Server.pick: when last time's connection was remote, give the plain home
  addresses 2 s first (a hairpinned remote address kept us encrypted and
  capped at home). test/PreferHomeTest.java.
- Playback "playing" but not moving for 12 s: say so instead of staying silent.
- Menu -> Close Minamp: stop the music and close every screen.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/strings.py

@@ -230,6 +230,34 @@ S = {
     "searching": ("Searching…", "Buscando…"),
     "nothing_found_q": ("Nothing found for “%1$s”", "Non se atopou nada para “%1$s”"),
 
+    # downloads (offline listening)
+    "downloads": ("Downloads", "Descargas"),
+    "download": ("Download", "Descargar"),
+    "remove_download": ("Remove download", "Borrar a descarga"),
+    "downloading_x": ("Downloading %1$s…", "Descargando %1$s…"),
+    "queued_n": ("%1$d tracks added to downloads", "%1$d pistas engadidas ás descargas"),
+    "already_downloaded": ("Already downloaded", "Xa está descargado"),
+    "dl_waiting": ("Waiting", "Agardando"),
+    "dl_progress": ("Downloading %1$d%%", "Descargando %1$d%%"),
+    "dl_failed": ("Failed: %1$s (tap to retry)", "Fallou: %1$s (toca para tentar de novo)"),
+    "dl_retrying": ("Will retry when the server is reachable", "Tentarase de novo cando se poida conectar co servidor"),
+    "dl_summary": ("%1$d tracks · %2$s · %3$s free", "%1$d pistas · %2$s · %3$s libres"),
+    "dl_empty": ("Nothing downloaded yet.\nLong-press an album, playlist or track and choose Download.",
+                 "Aínda non descargaches nada.\nMantén premido un álbum, lista ou pista e escolle Descargar."),
+    "dl_in_progress": ("In progress", "En curso"),
+    "dl_done_section": ("On this phone", "Neste teléfono"),
+    "dl_no_space": ("Not enough free space", "Non hai espazo libre abondo"),
+    "delete_all_downloads": ("Delete all downloads", "Borrar todas as descargas"),
+    "delete_all_confirm": ("Delete every downloaded track from this phone?", "Borrar deste teléfono todas as pistas descargadas?"),
+    "cancel_downloads": ("Cancel pending downloads", "Cancelar as descargas pendentes"),
+    "set_dl_quality": ("Download quality: %1$s", "Calidade das descargas: %1$s"),
+    "dl_quality_title": ("Download quality", "Calidade das descargas"),
+    "dl_quality_original": ("Original MP3s, others 320 kbps", "MP3 orixinais, o resto a 320 kbps"),
+    "set_delete_downloads": ("Delete all downloads (%1$s)", "Borrar todas as descargas (%1$s)"),
+    "downloaded": ("Downloaded", "Descargada"),
+    "quit_app": ("Close Minamp", "Pechar Minamp"),
+    "stalled": ("Playback is stuck. Try pausing and playing again.", "A reprodución quedou parada. Proba a pausar e reproducir de novo."),
+
     # pure-Java layers (looked up by name through com.minamp.util.Tr)
     "tr_kind_home": ("Home network", "Rede da casa"),
     "tr_kind_direct": ("Direct", "Directa"),