refactor: migrate to kotlinx serialization, eliminate gson dependency

gradle/libs.versions.toml

@@ -1,9 +1,7 @@
 [versions]
 agp = "9.2.1"
 biometric = "1.2.0-alpha05"
-converterGson = "3.0.0"
 coreKtx = "1.10.1"
-gson = "2.14.0"
 junit = "4.13.2"
 junitVersion = "1.1.5"
 espressoCore = "3.5.1"
@@ -34,14 +32,13 @@ benchmark = "1.4.1"
 runner = "1.5.2"
 androidx-test-ext = "1.2.1"
 timber = "5.0.1"
+kotlinx-serialization = "1.8.1"
 
 [libraries]
 androidx-biometric = { module = "androidx.biometric:biometric", version.ref = "biometric" }
 androidx-compose-animation = { module = "androidx.compose.animation:animation" }
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
 androidx-lifecycle-viewmodel-ktx = { module = "androidx.lifecycle:lifecycle-viewmodel-ktx", version.ref = "lifecycleViewmodelKtx" }
-converter-gson = { module = "com.squareup.retrofit2:converter-gson", version.ref = "converterGson" }
-gson = { module = "com.google.code.gson:gson", version.ref = "gson" }
 junit = { group = "junit", name = "junit", version.ref = "junit" }
 androidx-junit = { group = "androidx.test.ext", name = "junit", version.ref = "junitVersion" }
 androidx-espresso-core = { group = "androidx.test.espresso", name = "espresso-core", version.ref = "espressoCore" }
@@ -83,6 +80,9 @@ androidx-benchmark-junit4 = { group = "androidx.benchmark", name = "benchmark-ju
 androidx-runner = { group = "androidx.test", name = "runner", version.ref = "runner" }
 androidx-test-ext-junit = { group = "androidx.test.ext", name = "junit", version.ref = "androidx-test-ext" }
 timber = { group = "com.jakewharton.timber", name = "timber", version.ref = "timber" }
+kotlinx-serialization-json = { module = "org.jetbrains.kotlinx:kotlinx-serialization-json", version.ref = "kotlinx-serialization" }
+converter-kotlinx-serialization = { module = "com.squareup.retrofit2:converter-kotlinx-serialization", version.ref = "retrofit" }
+
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }
@@ -93,3 +93,4 @@ protobuf = { id = "com.google.protobuf", version.ref = "protobufPlugin" }
 androidx-benchmark = { id = "androidx.benchmark", version.ref = "benchmark" }
 android-library = { id = "com.android.library", version.ref = "agp" }
 android-test         = { id = "com.android.test", version.ref = "agp" }
+kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }