Podlite 1.12: a build for Android 4.1 (Xperia J) with ExoPlayer, speed and skip silences

- One build per Android level, as in Tenda and Plexamp Lite: build/Podlite.apk (Android 2.2+, versionCode 1308) and
  build/Podlite-api16.apk (Android 4.1+, 1316), from shared src/ plus platform/api8 or platform/api16; build.sh now
  runs on the local toolchain (aapt2, dx or R8, signapk.py; the JKS key converted for the run).
- Android 4.1 build: ExoPlayer 2.18.7 behind an Engine interface, with playback speed (player header) and skipping
  silences (Settings), a 3-minute buffer and MediaPlayer as fallback for audio it can't decode; a notification and
  lock screen with the cover and buttons; Holo; a menu button on phones without a Menu key; metered networks for
  "download on Wi-Fi only".
- Both builds: tlskit's Http.abort fix (a finished response's pooled connection is no longer closed under a later
  request); the lock screen's and newer headsets' play/pause keys.

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

spec.md

@@ -14,7 +14,7 @@ server and other apps.
 - Native Java, no libraries beyond the bundled TLS stack. All sizes in `res/values/dimens.xml`.
 - Galician interface; warm dark colours with an amber accent (from the radio icon).
 
-## Current scope (1.11)
+## Current scope (1.12)
 
 - Login with user/password (refreshes 2.26+ short-lived tokens; older servers' long-lived token) or an API key.
 - HTTP on the LAN; bundled TLS 1.2 for `https://` (Mozilla roots); other certificates shown by fingerprint,
@@ -25,9 +25,15 @@ server and other apps.
 - Progress sync every 15 s and on pause; offline positions sent later.
 - Headset buttons; pauses for calls and unplugging.
 
+## Android 4.1 build
+
+- `build/Podlite-api16.apk` (minSdk/targetSdk 16) next to `build/Podlite.apk` (API 8): shared `src/`, per-level
+  `platform/api8|api16/…/Platform.java` with the same methods, `platform/api16/res` overlaid. ExoPlayer with speed and
+  skip silences, notification and lock screen with cover and buttons, Holo, ⋮ without a Menu key, metered networks.
+
 ## Out of scope
 
-- Audiobooks, playback speed (Android 2.x can't), HLS/transcoded streams (so no Opus).
+- Audiobooks, HLS/transcoded streams (so no Opus); playback speed on Android 2.x (it can't).
 
 ## Must not break
 
@@ -35,6 +41,11 @@ server and other apps.
   reported, never marked played. A stall of 12 s is reported.
 - Package `com.miniabs` and `miniabs.keystore` (password `miniabs`): updates install over MiniABS.
 - `src/com/miniabs/net/` is a copy of `tlskit`: change it in `../tlskit` and reinstall.
+- `platform/api8` and `platform/api16` keep the same `Platform` methods; shared code calls no API the API 8 jar lacks
+  (the api8 compile and Dalvik check catch it). Each build's `versionCode` is the manifest's × 100 + level, same key;
+  both APKs are listed in `../tenda-lite/repo/apps.json`.
+- The Android 4.1 build targets API 16: network on the main thread is allowed in `Platform.init`; keep the desktop
+  tests' files (`Util`, `Api`…) free of `Platform`.
 - Installs to internal storage.
 
 ## Code map