refactor(frontend, build): update PingViewModel initialization, resolve view model via Koin, and clean yarn dependencies

Injected `PingViewModel` via Koin to align with dependency injection best practices. Suppressed Gradle deprecation warnings and added the `frontend.core.sync` dependency. Cleaned up outdated packages in `yarn.lock`.

frontend/core/local-db/build.gradle.kts

@@ -43,8 +43,6 @@ kotlin {
       implementation(libs.sqldelight.driver.web)
 
       // NPM deps used by `sqlite.worker.js` (OPFS-backed SQLite WASM worker)
-      implementation(npm("@cashapp/sqldelight-sqljs-worker", "2.2.1"))
-      // Use a published build tag from the official package.
       implementation(npm("@sqlite.org/sqlite-wasm", "3.51.1-build2"))
     }
 

frontend/core/local-db/src/commonMain/sqldelight/at/mocode/frontend/core/localdb/AppDatabase.sq

@@ -4,6 +4,14 @@ CREATE TABLE Task (
   is_completed INTEGER NOT NULL DEFAULT 0
 );
 
+CREATE TABLE PingEvent (
+  -- UUIDv7 as String (cursor-friendly and backend-compatible)
+  id TEXT NOT NULL PRIMARY KEY,
+  message TEXT NOT NULL,
+  -- Derived from UUIDv7 timestamp (epoch millis) for sorting/display
+  last_modified INTEGER NOT NULL
+);
+
 selectAll:
 SELECT *
 FROM Task;
@@ -15,3 +23,26 @@ VALUES ?;
 delete:
 DELETE FROM Task
 WHERE id = ?;
+
+selectPingEventsSince:
+SELECT *
+FROM PingEvent
+WHERE id > ?
+ORDER BY id;
+
+selectLatestPingEventId:
+SELECT id
+FROM PingEvent
+ORDER BY id DESC
+LIMIT 1;
+
+upsertPingEvents:
+-- SQLite dialect configured for this project is 3.18 (no UPSERT support).
+-- Use INSERT OR REPLACE as pragmatic upsert.
+INSERT OR REPLACE INTO PingEvent(id, message, last_modified)
+VALUES ?;
+
+upsertPingEvent:
+-- Single-row convenience upsert (used by repositories).
+INSERT OR REPLACE INTO PingEvent(id, message, last_modified)
+VALUES (?, ?, ?);

frontend/core/sync/build.gradle.kts

@@ -0,0 +1,33 @@
+plugins {
+  alias(libs.plugins.kotlinMultiplatform)
+  alias(libs.plugins.kotlinSerialization)
+}
+
+kotlin {
+  // Targets are configured centrally in the shells/feature modules; here we just provide common code.
+  jvm()
+  js(IR) {
+    browser()
+  }
+
+  sourceSets {
+    commonMain.dependencies {
+      implementation(projects.core.coreDomain)
+
+      // Networking
+      implementation(libs.ktor.client.core)
+      implementation(libs.ktor.client.contentNegotiation)
+      implementation(libs.ktor.client.serialization.kotlinx.json)
+
+      // Serialization
+      implementation(libs.kotlinx.serialization.json)
+
+      // DI
+      implementation(libs.koin.core)
+    }
+
+    commonTest.dependencies {
+      implementation(libs.kotlin.test)
+    }
+  }
+}

frontend/core/sync/src/commonMain/kotlin/at/mocode/frontend/core/sync/SyncCore.kt

@@ -0,0 +1,54 @@
+package at.mocode.frontend.core.sync
+
+import at.mocode.core.sync.Syncable
+import io.ktor.client.HttpClient
+import io.ktor.client.call.body
+import io.ktor.client.request.get
+import io.ktor.client.request.parameter
+
+/**
+ * Minimaler Repository-Contract für Delta-Sync.
+ */
+interface SyncableRepository<T : Syncable> {
+  /**
+   * Cursor für Delta-Sync.
+   *
+   * Konvention: UUIDv7 als String (Backend kann `>` vergleichen) oder ein kompatibler Cursor.
+   *
+   * @return letzter bekannter Cursor lokal oder `null`, wenn noch keine Daten existieren.
+   */
+  suspend fun getLatestSince(): String?
+
+  /** Insert oder Update (Upsert) der übergebenen Items. */
+  suspend fun upsert(items: List<T>)
+}
+
+/**
+ * Generischer Sync-Manager.
+ *
+ * Konvention Backend:
+ * - GET `/api/{entity-plural}/sync?since={timestamp}`
+ * - Response: `List<T>`
+ */
+class SyncManager(
+  val ktorClient: HttpClient
+) {
+
+  suspend inline fun <reified T : Syncable> performSync(
+    repository: SyncableRepository<T>,
+    endpointPath: String
+  ) {
+    val since = repository.getLatestSince()
+
+    val remoteItems: List<T> = ktorClient
+      .get(endpointPath) {
+        // `since` optional
+        if (since != null) parameter("since", since)
+      }
+      .body()
+
+    if (remoteItems.isNotEmpty()) {
+      repository.upsert(remoteItems)
+    }
+  }
+}

frontend/core/sync/src/commonMain/kotlin/at/mocode/frontend/core/sync/di/SyncModule.kt

@@ -0,0 +1,12 @@
+package at.mocode.frontend.core.sync.di
+
+import at.mocode.frontend.core.sync.SyncManager
+import org.koin.dsl.module
+
+/**
+ * Zentrales Koin-Modul für den Sync-Core.
+ */
+val syncModule = module {
+  // Provides a singleton instance of SyncManager, using the globally provided HttpClient.
+  single { SyncManager(get()) }
+}