feat(folio): introduce Metro AppGraph in commonMain

Single shared @DependencyGraph(AppScope::class) that exposes
Repository, Navigator, and ViewModels. LedgerDatabase enters the
graph via @DependencyGraph.Factory.create(database) so the suspend
DriverFactory.create() can stay outside the DI surface.

@Binds wires SqlLedgerStore to LedgerStore; Navigator is provided
explicitly so its Route.Home start state stays in DI rather than
relying on a default-parameter being honored by the graph.

examples/folio/app/shared/src/commonMain/kotlin/app/folio/di/AppGraph.kt

@@ -0,0 +1,42 @@
+package app.folio.di
+
+import app.folio.core.data.LedgerStore
+import app.folio.core.data.Repository
+import app.folio.core.data.SqlLedgerStore
+import app.folio.db.LedgerDatabase
+import app.folio.feature.account.AddAccountViewModel
+import app.folio.feature.auth.LoginViewModel
+import app.folio.feature.home.HomeViewModel
+import app.folio.feature.ledger.AddTransactionViewModel
+import app.folio.feature.ledger.LedgerViewModel
+import app.folio.navigation.Navigator
+import app.folio.navigation.Route
+import dev.zacsweers.metro.AppScope
+import dev.zacsweers.metro.Binds
+import dev.zacsweers.metro.DependencyGraph
+import dev.zacsweers.metro.Provides
+import dev.zacsweers.metro.SingleIn
+
+@SingleIn(AppScope::class)
+@DependencyGraph(AppScope::class)
+interface AppGraph {
+    val repository: Repository
+    val navigator: Navigator
+
+    val loginViewModel: LoginViewModel
+    val homeViewModel: HomeViewModel
+    val addAccountViewModel: AddAccountViewModel
+    val ledgerViewModelFactory: LedgerViewModel.Factory
+    val addTransactionViewModelFactory: AddTransactionViewModel.Factory
+
+    @Binds val SqlLedgerStore.bindLedgerStore: LedgerStore
+
+    @SingleIn(AppScope::class)
+    @Provides
+    fun provideNavigator(): Navigator = Navigator(initial = Route.Home)
+
+    @DependencyGraph.Factory
+    fun interface Factory {
+        fun create(@Provides database: LedgerDatabase): AppGraph
+    }
+}