M2b: Android skeleton, :core:model contract, :domain passing all vectors

Gradle project in android/ with every module of SPEC §6.2 (build-logic convention plugins, version catalog,
architecture check in check), :core:model types and repository interfaces of §14.2.4 and §14.5, :domain
implementing §14.5.2 and §14.5.4 (125 vector cases), scenario-driven fakes with the empty scenario, Room 3
entities and KvittDatabase v1 with exported schema, :app shell with Hilt, en/sv strings with MissingTranslation
as a lint error, Roborazzi goldens of the empty screen in light and dark.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

android/app/src/test/kotlin/se/hagstedt/kvitt/KvittEmptyScreenScreenshotTest.kt

@@ -0,0 +1,38 @@
+package se.hagstedt.kvitt
+
+import androidx.compose.ui.test.junit4.v2.createComposeRule
+import androidx.compose.ui.test.onRoot
+import com.github.takahirom.roborazzi.captureRoboImage
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
+import se.hagstedt.kvitt.design.KvittTheme
+
+/**
+ * Golden screenshots of the empty screen in light and dark (Roborazzi on Robolectric). `check` verifies them;
+ * re-record an intended change with `tools/gradle-serial.sh recordRoborazziDebug` and open every changed PNG.
+ * Viewport: the Galaxy S26 (about 411 x 891 dp, SPEC §13.1).
+ */
+@RunWith(RobolectricTestRunner::class)
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+@Config(sdk = [36], qualifiers = "w411dp-h891dp-xxhdpi")
+class KvittEmptyScreenScreenshotTest {
+    @get:Rule
+    val compose = createComposeRule()
+
+    @Test
+    fun emptyScreenLight() = capture(darkTheme = false, name = "empty_screen_light")
+
+    @Test
+    fun emptyScreenDark() = capture(darkTheme = true, name = "empty_screen_dark")
+
+    private fun capture(darkTheme: Boolean, name: String) {
+        compose.setContent {
+            KvittTheme(darkTheme = darkTheme) { KvittEmptyScreen() }
+        }
+        compose.onRoot().captureRoboImage("src/test/screenshots/$name.png")
+    }
+}