REDI-93: host the Views list in the Compose NavHost (Compose<->View interop)

:app now owns the cross-toolkit interop. MainActivity becomes a FragmentActivity and
hosts CharacterListFragment inside the Compose NavHost via AndroidFragment at a new
@Serializable CharactersViewsRoute (defined in :app, since :app owns interop — the Views
module stays nav-agnostic). The overflow menu's 'Open as Views' / 'About' entries and the
Views item-click -> detail navigation are all injected as callbacks, keeping the renderers
decoupled. Assemble aboutPresentationModule in Koin; add androidx.fragment:fragment-compose.
The Material3 Activity theme styles both toolkits.

app/build.gradle.kts

@@ -2,6 +2,8 @@ plugins {
     alias(libs.plugins.architecture.android.application)
     alias(libs.plugins.architecture.compose)
     alias(libs.plugins.architecture.koin)
+    // For the @Serializable CharactersViewsRoute (Compose↔View interop destination).
+    alias(libs.plugins.architecture.kotlinx.serialization)
 }
 
 android {
@@ -16,16 +18,23 @@ dependencies {
     implementation(project(":core:data"))
     implementation(project(":core:design-system"))
 
-    // Characters feature: data + presentation (Koin modules) + Compose renderer (nav graph).
+    // Characters feature: data + presentation (Koin modules) + both renderers (Compose nav graph,
+    // Views Fragment hosted via interop).
     implementation(project(":feature:characters:data"))
     implementation(project(":feature:characters:presentation"))
     implementation(project(":feature:characters:presentation-compose"))
+    implementation(project(":feature:characters:presentation-views"))
+
+    // About feature (MVVM contrast).
+    implementation(project(":feature:about:presentation"))
 
     implementation(libs.androidx.core.ktx)
     implementation(libs.androidx.activity.compose)
     implementation(libs.androidx.lifecycle.runtime.ktx)
     implementation(libs.bundles.lifecycle.compose)
     implementation(libs.androidx.navigation.compose)
+    // Compose↔View interop: hosts a Fragment inside the Compose NavHost.
+    implementation(libs.androidx.fragment.compose)
     // Material Components — required for the Material3 XML Activity theme.
     implementation(libs.material)
     // Logging — the DebugTree is planted here; other modules log via Timber's static API.

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

@@ -2,6 +2,7 @@ package com.example.architecture
 
 import android.app.Application
 import com.example.architecture.core.data.di.coreDataModule
+import com.example.architecture.feature.about.presentation.di.aboutPresentationModule
 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
@@ -31,6 +32,8 @@ class ArchitectureApp : Application() {
                 // characters feature
                 charactersDataModule,
                 charactersPresentationModule,
+                // about feature (MVVM contrast)
+                aboutPresentationModule,
             )
         }
     }

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

@@ -0,0 +1,11 @@
+package com.example.architecture
+
+import kotlinx.serialization.Serializable
+
+/**
+ * Route for the characters list rendered with the classic **Views** toolkit. It lives in `:app`
+ * because `:app` owns Compose↔View interop — the `:feature:characters:presentation-views` module
+ * stays navigation-agnostic (it knows nothing about Compose Navigation or this route).
+ */
+@Serializable
+data object CharactersViewsRoute

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

@@ -1,16 +1,30 @@
 package com.example.architecture
 
 import android.os.Bundle
-import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import androidx.fragment.app.FragmentActivity
+import androidx.fragment.compose.AndroidFragment
 import androidx.navigation.compose.NavHost
+import androidx.navigation.compose.composable
 import androidx.navigation.compose.rememberNavController
 import com.example.architecture.core.design.system.theme.AppTheme
+import com.example.architecture.feature.about.presentation.AboutRoute
+import com.example.architecture.feature.about.presentation.aboutGraph
+import com.example.architecture.feature.characters.presentation.compose.CharacterDetailRoute
 import com.example.architecture.feature.characters.presentation.compose.CharacterListRoute
 import com.example.architecture.feature.characters.presentation.compose.charactersGraph
+import com.example.architecture.feature.characters.presentation.views.CharacterListFragment
 
-class MainActivity : ComponentActivity() {
+/**
+ * Hosts the single Compose NavHost and owns every cross-feature / cross-toolkit wiring:
+ * - the characters graph (Compose list + detail),
+ * - the About graph (MVVM contrast),
+ * - the Views renderer embedded via [AndroidFragment] (Compose↔View interop).
+ *
+ * Extends [FragmentActivity] (not plain ComponentActivity) so [AndroidFragment] has a FragmentManager.
+ */
+class MainActivity : FragmentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         enableEdgeToEdge()
@@ -22,8 +36,23 @@ class MainActivity : ComponentActivity() {
                     startDestination = CharacterListRoute,
                 ) {
                     charactersGraph(
-                        onCharacterClick = { /* Detail navigation is wired in the next milestone. */ },
+                        navController = navController,
+                        onOpenAbout = { navController.navigate(AboutRoute) },
+                        onOpenViewsList = { navController.navigate(CharactersViewsRoute) },
                     )
+                    aboutGraph(
+                        onNavigateBack = { navController.popBackStack() },
+                    )
+                    // Compose↔View interop: the same characters list, rendered by a Fragment. :app
+                    // injects the navigation callbacks so the Views module stays nav-agnostic.
+                    composable<CharactersViewsRoute> {
+                        AndroidFragment<CharacterListFragment> { fragment ->
+                            fragment.onCharacterClick = { id ->
+                                navController.navigate(CharacterDetailRoute(id))
+                            }
+                            fragment.onNavigateBack = { navController.popBackStack() }
+                        }
+                    }
                 }
             }
         }