start kotlin/jetpack compose rewrite

replace the flutter project with a gradle/compose android app:
- nix flake dev shell (jdk21, android sdk 35, build-tools 37, gradle)
- material3 app with a placeholder screen
- roborazzi/robolectric screenshot tests with one golden
- carry over the existing launcher/notification assets

app/src/test/kotlin/com/subtracks/ui/HelloScreenshotTest.kt

@@ -0,0 +1,32 @@
+package com.subtracks.ui
+
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import androidx.compose.ui.test.onRoot
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.github.takahirom.roborazzi.RobolectricDeviceQualifiers
+import com.github.takahirom.roborazzi.captureRoboImage
+import com.subtracks.ui.theme.SubtracksTheme
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
+
+@RunWith(AndroidJUnit4::class)
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+@Config(qualifiers = RobolectricDeviceQualifiers.PixelXL)
+class HelloScreenshotTest {
+    @get:Rule
+    val composeRule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test
+    fun hello() {
+        composeRule.setContent {
+            SubtracksTheme {
+                HelloScreen()
+            }
+        }
+        composeRule.onRoot().captureRoboImage("src/test/screenshots/hello.png")
+    }
+}

app/src/test/resources/robolectric.properties

@@ -0,0 +1 @@
+sdk=34