feat: Deserialize directly to OffsetDateTime, not String

app/build.gradle.kts

@@ -49,6 +49,7 @@ dependencies {
     implementation("androidx.core:core-splashscreen:1.0.1")
     implementation("com.squareup.retrofit2:retrofit:2.11.0")
     implementation("com.squareup.retrofit2:converter-gson:2.11.0")
+    implementation("com.fatboyindustrial.gson-javatime-serialisers:gson-javatime-serialisers:1.1.2")
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.10.1")
     implementation("com.jakewharton.threetenabp:threetenabp:1.4.4")
 }

app/src/main/java/com/p_vacho/neat_calendar/api/RetrofitClient.kt

@@ -2,6 +2,7 @@ package com.p_vacho.neat_calendar.api
 
 import android.content.Context
 import android.util.Log
+import com.google.gson.GsonBuilder
 import com.p_vacho.neat_calendar.api.services.AuthService
 import com.p_vacho.neat_calendar.api.services.GeneralService
 import okhttp3.OkHttpClient
@@ -11,6 +12,8 @@ import com.p_vacho.neat_calendar.api.interceptors.AuthInterceptor
 import okhttp3.ResponseBody
 import retrofit2.HttpException
 import java.io.IOException
+import java.time.OffsetDateTime
+import com.fatboyindustrial.gsonjavatime.OffsetDateTimeConverter
 
 object RetrofitClient {
     private const val DEFAULT_BASE_URL = "http://10.0.2.2:8000"
@@ -62,10 +65,15 @@ object RetrofitClient {
             okHttpClient.addInterceptor(ApiReachabilityInterceptor(appContext))
         }
         okHttpClient.addInterceptor(AuthInterceptor(appContext))
+
+        val gson = GsonBuilder()
+            .registerTypeAdapter(OffsetDateTime::class.java, OffsetDateTimeConverter())
+            .create()
+
         return Retrofit.Builder()
             .baseUrl(baseUrl)
             .client(okHttpClient.build())
-            .addConverterFactory(GsonConverterFactory.create())
+            .addConverterFactory(GsonConverterFactory.create(gson))
             .build()
     }
 

app/src/main/java/com/p_vacho/neat_calendar/api/models/AuthModels.kt

@@ -1,5 +1,7 @@
 package com.p_vacho.neat_calendar.api.models
 
+import java.time.OffsetDateTime
+
 data class LoginResponse(
     val access_token: String,
     val expires_in: Int,
@@ -20,8 +22,8 @@ data class SessionResponse(
     val id: String,
     val session_type: String, // "refresh" or "access"
     val parent_session_id: String?,
-    val expires_at: String, // ISO 8601
-    val created_at: String, // ISO 8601
+    val expires_at: OffsetDateTime,
+    val created_at: OffsetDateTime,
     val revoked: Boolean,
 )
 
@@ -35,5 +37,5 @@ data class RegisterResponse(
     val user_id: String,
     val username: String,
     val email: String,
-    val created_at: String, // ISO 8601
+    val created_at: OffsetDateTime,
 )