all: refactor model classes and serialization

- Move model classes to a standalone `model` Gradle module
- Migrate from Moshi to kotlinx.serialization for multiplatform support

android/build.gradle.kts

@@ -23,7 +23,8 @@ dependencies {
   implementation(libs.androidx.paging.compose)
   implementation(libs.dagger.hilt.android)
   implementation(libs.sqldelight.extensions.coroutines)
-  implementation(libs.retrofit.moshiConverter)
+  implementation(libs.kotlinx.serialization.json)
+  implementation(libs.retrofit.kotlinxSerializationConverter) { isTransitive = false }
 }
 
 android {

android/proguard-rules.pro

@@ -12,3 +12,21 @@
 -keep,allowobfuscation,allowshrinking class dev.msfjarvis.claw.android.** { *; }
 
 -dontobfuscate
+
+-keepattributes *Annotation*, InnerClasses
+-dontnote kotlinx.serialization.AnnotationsKt
+
+-keepclassmembers class kotlinx.serialization.json.** {
+    *** Companion;
+}
+-keepclasseswithmembers class kotlinx.serialization.json.** {
+    kotlinx.serialization.KSerializer serializer(...);
+}
+
+-keep,includedescriptorclasses class dev.msfjarvis.claw.model.**$$serializer { *; }
+-keepclassmembers class dev.msfjarvis.claw.model.** {
+    *** Companion;
+}
+-keepclasseswithmembers class dev.msfjarvis.claw.model.** {
+    kotlinx.serialization.KSerializer serializer(...);
+}

android/src/main/kotlin/dev/msfjarvis/claw/android/ext/database.kt

@@ -1,7 +1,7 @@
 package dev.msfjarvis.claw.android.ext
 
-import dev.msfjarvis.claw.api.model.LobstersPost
 import dev.msfjarvis.claw.database.local.SavedPost
+import dev.msfjarvis.claw.model.LobstersPost
 
 /** Convert a [LobstersPost] object returned by the API into a [SavedPost] for persistence. */
 fun LobstersPost.toDbModel(): SavedPost {

android/src/main/kotlin/dev/msfjarvis/claw/android/injection/ApiModule.kt

@@ -1,18 +1,21 @@
 package dev.msfjarvis.claw.android.injection
 
 import android.util.Log
-import com.squareup.moshi.Moshi
+import com.jakewharton.retrofit2.converter.kotlinx.serialization.asConverterFactory
 import dagger.Lazy
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.InstallIn
 import dagger.hilt.components.SingletonComponent
 import dev.msfjarvis.claw.api.LobstersApi
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.json.Json
+import okhttp3.MediaType
 import okhttp3.OkHttpClient
 import retrofit2.Retrofit
-import retrofit2.converter.moshi.MoshiConverterFactory
 import retrofit2.create
 
+@OptIn(ExperimentalSerializationApi::class)
 @Module
 @InstallIn(SingletonComponent::class)
 object ApiModule {
@@ -35,12 +38,12 @@ object ApiModule {
   @Provides
   fun provideRetrofit(
     client: Lazy<OkHttpClient>,
-    moshi: Lazy<Moshi>,
   ): Retrofit {
+    val contentType = MediaType.get("application/json")
     return Retrofit.Builder()
       .client(client.get())
       .baseUrl(LobstersApi.BASE_URL)
-      .addConverterFactory(MoshiConverterFactory.create(moshi.get()))
+      .addConverterFactory(Json.asConverterFactory(contentType))
       .build()
   }
 

android/src/main/kotlin/dev/msfjarvis/claw/android/injection/MoshiModule.kt

@@ -1,18 +0,0 @@
-package dev.msfjarvis.claw.android.injection
-
-import com.squareup.moshi.Moshi
-import dagger.Module
-import dagger.Provides
-import dagger.Reusable
-import dagger.hilt.InstallIn
-import dagger.hilt.components.SingletonComponent
-
-@Module
-@InstallIn(SingletonComponent::class)
-object MoshiModule {
-  @Provides
-  @Reusable
-  fun provideMoshi(): Moshi {
-    return Moshi.Builder().build()
-  }
-}

android/src/main/kotlin/dev/msfjarvis/claw/android/paging/LobstersPagingSource.kt

@@ -2,7 +2,7 @@ package dev.msfjarvis.claw.android.paging
 
 import androidx.paging.PagingSource
 import androidx.paging.PagingState
-import dev.msfjarvis.claw.api.model.LobstersPost
+import dev.msfjarvis.claw.model.LobstersPost
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/NetworkPosts.kt

@@ -14,9 +14,9 @@ import androidx.compose.ui.unit.dp
 import androidx.paging.compose.LazyPagingItems
 import androidx.paging.compose.items
 import dev.msfjarvis.claw.android.ext.toDbModel
-import dev.msfjarvis.claw.api.model.LobstersPost
 import dev.msfjarvis.claw.common.posts.LobstersCard
 import dev.msfjarvis.claw.database.local.SavedPost
+import dev.msfjarvis.claw.model.LobstersPost
 import kotlinx.coroutines.launch
 
 @Composable