feat(02-06): wire auth session into koin

- provide authModule singletons for store, OIDC, MeClient, AuthSession, and HttpClient
- include authModule from appModule bootstrap

composeApp/src/commonMain/kotlin/dev/ulfrx/recipe/auth/AuthModule.kt

@@ -0,0 +1,19 @@
+package dev.ulfrx.recipe.auth
+
+import io.ktor.client.HttpClient
+import org.koin.dsl.module
+
+val authModule =
+    module {
+        single<SecureAuthStateStore> { SecureAuthStateStore() }
+        single<OidcClient> { OidcClient() }
+        single<MeClient> { MeClient() }
+        single<AuthSession> {
+            AuthSession(
+                oidcClient = get<OidcClient>(),
+                store = get<SecureAuthStateStore>(),
+                meClient = get<MeClient>(),
+            )
+        }
+        single<HttpClient> { AuthHttpClient.create(get()) }
+    }

composeApp/src/commonMain/kotlin/dev/ulfrx/recipe/di/AppModule.kt

@@ -1,9 +1,10 @@
 package dev.ulfrx.recipe.di
 
+import dev.ulfrx.recipe.auth.authModule
 import org.koin.dsl.module
 
 // Phase 2 adds authModule; Phase 4 adds syncModule; Phase 5 adds catalogModule; etc.
 val appModule =
     module {
-        // intentionally empty in Phase 1
+        includes(authModule)
     }