improved android client, feature parity with desktop

android/app/proguard-test-rules.pro

@@ -0,0 +1,11 @@
+# Applied only to the instrumentation APK when androidTest runs against a
+# minified build (ANDROID_TEST_BUILD_TYPE=release). The tests exist to prove the
+# *app's* R8 configuration is right, so nothing here may relax the app's rules —
+# it only keeps the test harness itself intact.
+-dontobfuscate
+-keep class io.narl.protonstream.** { *; }
+-keep class androidx.test.** { *; }
+-dontwarn androidx.test.**
+-keepclasseswithmembers class * {
+    @org.junit.Test <methods>;
+}