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/core/fakes/build.gradle.kts

@@ -0,0 +1,12 @@
+// :core:fakes — scenario-driven fakes of every repository interface of SPEC §14.2.4. Only for tests, screenshot tests
+// and debug previews (the architecture check rejects it in release configurations). Computed values come from :domain.
+// M7x add their scenarios under src/main/kotlin/se/hagstedt/kvitt/fakes/<feature>/ and nowhere else (SPEC §11.3).
+plugins {
+    id("kvitt.android.library")
+}
+
+dependencies {
+    api(project(":core:model"))
+    implementation(project(":domain"))
+    testImplementation(libs.kotlinx.coroutines.test)
+}