feat(mobile): self-update dialog with verified APK download and install (M5)

Checks the server for a newer release at most every 6 hours and on
demand in Profile, shows release notes, downloads the APK with progress,
verifies SHA-256 in 1 MB chunks and hands it to the system installer.
Updates below min_supported cannot be dismissed.

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

packages/i18n/locales/en/common.json

@@ -201,6 +201,20 @@
     "open_player": "Open the player",
     "close_player": "Collapse the player",
     "queue": "Queue",
-    "forget_server": "Forget server"
+    "forget_server": "Forget server",
+    "update_check": "Check for updates",
+    "update_checking": "Checking…",
+    "update_latest": "You have the latest version",
+    "update_title": "Version {{version}} is available",
+    "update_required": "The server no longer supports this version — please update the app",
+    "update_size": "Size {{size}} MB",
+    "update_install": "Download and install",
+    "update_later": "Later",
+    "update_downloading": "Downloading {{percent}}%",
+    "update_verifying": "Verifying the file…",
+    "update_bad_checksum": "The file is corrupted — try again",
+    "update_failed": "Could not download the update",
+    "update_allow": "Allow installing apps from this app in Android settings",
+    "update_open_settings": "Open settings"
   }
 }