Auto-check GitHub Releases latest on launch (24h throttle), show an
update banner on the home screen, download the APK in-app with progress,
and trigger the system installer via FileProvider + REQUEST_INSTALL_PACKAGES.
- core/UpdateChecker: fetch releases/latest, semver compare, stream APK
to externalFilesDir, install via FileProvider (handles MIUI unknown-sources).
- SettingsStore: updateCheckEnabled / lastUpdateCheckTime / ignoredVersion.
- HomeScreen: update banner + UpdateDialog.
- SettingsScreen: "关于与更新" card with auto-check toggle and manual check.
- manifest: REQUEST_INSTALL_PACKAGES + FileProvider; new res/xml/file_paths.xml.
- version 1.4.2 -> 1.5.0 (versionCode 7 -> 8).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>