M5: Android data layer: DAOs, Ktor client and DTOs, token store, sync engine and workers, repositories, APK updater

DAOs on M2b's Room 3 entities and KvittDatabase v1 (schema 1.json unchanged), DTOs for every wire
object and endpoint body with a round-trip test over all 80 contract examples, the Ktor client with the
section 14.3.1 headers and 14.3.2 error mapping, the Keystore-encrypted token store in auth.preferences_pb,
the sync engine of section 14.4 (push batches, pull pages, epoch recovery, rejections, clock skew, 401 and
426 handling) tested with MockEngine including AC-15.6, WorkManager triggers, every :core:model repository,
the APK updater behind an installer interface, Coil pictures, Hilt modules, Room migration test
infrastructure. Fakes: the five settled TODO(spec) comments resolved per SPEC v0.4 (settlement row in an
account's ledger carries that account's allocation).

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

android/data/build.gradle.kts

@@ -1,9 +1,12 @@
-// :data — Room database, Ktor client, sync engine and the real repositories (owned by M5). M2b ships the Room
-// entities of SPEC §14.2 and the database class with its exported schema (version 1), no DAOs.
+// :data — Room database, Ktor client, token store, sync engine, WorkManager workers, the real repositories and the APK
+// updater (SPEC §6.2, §14.2, §14.4; owned by M5). Hilt modules here provide the implementations; :app (M8) binds the
+// :core:model interfaces to them.
 plugins {
     id("kvitt.android.library")
+    id("kvitt.android.hilt")
     alias(libs.plugins.ksp)
     alias(libs.plugins.room3)
+    alias(libs.plugins.kotlin.serialization)
 }
 
 room3 {
@@ -15,4 +18,31 @@ dependencies {
     implementation(project(":domain"))
     implementation(libs.androidx.room3.runtime)
     ksp(libs.androidx.room3.compiler)
+    implementation(libs.androidx.sqlite.bundled)
+    implementation(libs.androidx.datastore.preferences)
+    implementation(libs.androidx.work.runtime.ktx)
+    implementation(libs.ktor.client.core)
+    implementation(libs.ktor.client.okhttp)
+    implementation(libs.ktor.client.content.negotiation)
+    implementation(libs.ktor.serialization.kotlinx.json)
+    implementation(libs.kotlinx.serialization.json)
+    implementation(libs.kotlinx.coroutines.core)
+    implementation(libs.kotlinx.datetime)
+    implementation(libs.coil)
+    implementation(libs.coil.network.ktor3)
+
+    testImplementation(libs.ktor.client.mock)
+    testImplementation(libs.kotlinx.coroutines.test)
+    testImplementation(libs.robolectric)
+}
+
+// Unit tests read the shared examples (SPEC §14.3.5) and the exported Room schemas (§14.2.3) in place; both are inputs,
+// so a changed contract file re-runs the tests.
+val contractsExamples = rootProject.layout.projectDirectory.dir("../contracts/examples")
+val roomSchemas = layout.projectDirectory.dir("schemas")
+tasks.withType<Test>().configureEach {
+    inputs.dir(contractsExamples).withPathSensitivity(PathSensitivity.RELATIVE).withPropertyName("contractsExamples")
+    inputs.dir(roomSchemas).withPathSensitivity(PathSensitivity.RELATIVE).withPropertyName("roomSchemas")
+    systemProperty("kvitt.contracts.examples", contractsExamples.asFile.absolutePath)
+    systemProperty("kvitt.room.schemas", roomSchemas.asFile.absolutePath)
 }