* feat(mobile): run on Android
The app builds and runs on Android, and fits there.
- Back button and gesture close what is open over the screen, then go
back a screen, and from the first one send the app to the background.
Left to the WebView they closed the app, since it has no history.
- The system bars: the page asks their size of the app (`insets`, over
JNI), since WebViews before 140 report the safe areas as 0 even edge
to edge. The CSS reads them as `--inset-*`, which iOS still fills
from `env()`.
- The keyboard: edge to edge, the WebView is not resized for it and its
visual viewport stays whole, so the keyboard covered the message box.
MainActivity hands its height to the page, which lays out as on iOS.
- The title folds into the bar from the scroll position on every screen.
The observer it used reported a title in plain view as out of sight on
Android, so the bar started folded.
- src-tauri/gen/android is kept in the repo for that MainActivity.
* ci(mobile): release a signed Android APK
A `mobile-v<x.y.z>` tag builds the app for arm64 at that version, signs
it with the release key and attaches it to a draft release. The mobile
app is versioned apart from the desktop's `v*` tags.
- The release is never marked latest: the desktop updater reads
/releases/latest and would take it for a desktop release.
- The APK's certificate is checked against the release key's, since one
signed with another key could not be installed over earlier ones.
- The NDK is pinned, and the version must be x.y.z: Tauri derives the
versionCode from it, and Android installs over a build only when that
is higher.
- Gradle signs a release build when keystore.properties names a key;
CI writes it from secrets.
- The release library is stripped: 30 MB to 20, the APK 32 to 23.
* ci: tell people how to install the phone app
The nightly release notes and each mobile-v release now say how to get
the app on a phone: the TestFlight link for iPhone, and the newest
mobile-v release's APK for Android. Both read .github/mobile-install.md.
