feat(characters): Koin module + nav graph + wire into :app (REDI-89)

- charactersPresentationModule: viewModelOf(::CharacterListViewModel) (in the UI-agnostic module).
- @Serializable CharacterListRoute + NavGraphBuilder.charactersGraph { composable<CharacterListRoute> }
  in presentation-compose (serialization plugin added for type-safe routes).
- :app registers coreDataModule + charactersDataModule + charactersPresentationModule in startKoin,
  and hosts a NavHost(startDestination = CharacterListRoute) calling charactersGraph.
- core:data manifest declares INTERNET (merges into :app) for live API calls.

app/src/main/kotlin/com/example/architecture/ArchitectureApp.kt

@@ -2,14 +2,16 @@ package com.example.architecture
 
 import android.app.Application
 import com.example.architecture.core.data.di.coreDataModule
+import com.example.architecture.feature.characters.data.di.charactersDataModule
+import com.example.architecture.feature.characters.presentation.di.charactersPresentationModule
 import org.koin.android.ext.koin.androidContext
 import org.koin.android.ext.koin.androidLogger
 import org.koin.core.context.startKoin
 import timber.log.Timber
 
 /**
- * Single Koin entry point. Feature modules append their own `*DataModule` / `*PresentationModule`
- * to the [modules] list — assembly happens only here, never inside feature modules.
+ * Single Koin entry point. Every feature's `*DataModule` / `*PresentationModule` is assembled here,
+ * never inside feature modules.
  */
 class ArchitectureApp : Application() {
     override fun onCreate() {
@@ -24,7 +26,11 @@ class ArchitectureApp : Application() {
             androidLogger()
             androidContext(this@ArchitectureApp)
             modules(
+                // core
                 coreDataModule,
+                // characters feature
+                charactersDataModule,
+                charactersPresentationModule,
             )
         }
     }

app/src/main/kotlin/com/example/architecture/MainActivity.kt

@@ -4,31 +4,26 @@ import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.padding
-import androidx.compose.material3.Text
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import com.example.architecture.core.design.system.component.AppScaffold
+import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.rememberNavController
 import com.example.architecture.core.design.system.theme.AppTheme
+import com.example.architecture.feature.characters.presentation.compose.CharacterListRoute
+import com.example.architecture.feature.characters.presentation.compose.charactersGraph
 
 class MainActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         enableEdgeToEdge()
         setContent {
-            // Compose themes via AppTheme; the navigation host lands in a later milestone.
             AppTheme {
-                AppScaffold { innerPadding ->
-                    Box(
-                        modifier = Modifier
-                            .fillMaxSize()
-                            .padding(innerPadding),
-                        contentAlignment = Alignment.Center,
-                    ) {
-                        Text(text = "Android Architecture Showcase")
-                    }
+                val navController = rememberNavController()
+                NavHost(
+                    navController = navController,
+                    startDestination = CharacterListRoute,
+                ) {
+                    charactersGraph(
+                        onCharacterClick = { /* Detail navigation is wired in the next milestone. */ },
+                    )
                 }
             }
         }