- PostIt.Android.csproj: drop Xamarin.AndroidX.Core.SplashScreen and
Xamarin.AndroidX.Browser. Neither is pulled transitively by
Avalonia.Android 12.1.1 (its nuspec declares only AppCompat +
Window), and they are not referenced anywhere in PostIt code.
- Resources/values-v31/styles.xml: drop the windowSplashScreen*
items and the 'postSplashScreenTheme' reference, which require
the dropped SplashScreen package. We fall back to the system
splash screen on Android 12+ devices; a custom one can come
back when we add it on purpose.
The earlier commit removed the client_secret and wired
MainActivity.OnNewIntent to AndroidOidcCallbackSink, but
IdentityModel.OidcClient.LoginAsync still had no IBrowser to drive
the user-agent half of the flow. Without it, the desktop / browser
projects continue to fail at login with 'No browser is available'.
Android now plugs in Chrome Custom Tabs:
* PostIt.Android/Services/AndroidSystemBrowser.cs implements
IBrowser.InvokeAsync using CustomTabsIntent.LaunchUrl and waits
for MainActivity.AndroidOidcCallbackSink to deliver the deep-link
Intent (android://postit-signin?code=...&state=...).
* PostIt/Services/Platform.cs is a tiny static indirection the
shared library uses to ask the running platform for an
IBrowser and the appropriate default RedirectUri, without
referencing any UI framework from the shared assembly.
* LoginPageViewModel reads Platform.DefaultRedirectUri and
Platform.CreateBrowser().Invoke() before calling LoginAsync.
* PostIt.Android/PlatformBootstrap.cs wires the Android side at
startup, and MainActivity.OnCreate calls EnsureInitialized().
* Xamarin.AndroidX.Browser 1.8.0 added to the central package
versions so CustomTabsIntent resolves.
