refactor: migrate to kotlinx serialization, eliminate gson dependency

app/build.gradle.kts

@@ -17,6 +17,7 @@ plugins {
     alias(libs.plugins.kotlin.compose)
     alias(libs.plugins.ksp)
     alias(libs.plugins.protobuf)
+    alias(libs.plugins.kotlin.serialization)
 }
 
 android {
@@ -132,7 +133,7 @@ dependencies {
 
     // Networking
     implementation(libs.retrofit2.retrofit)
-    implementation(libs.converter.gson)
+    implementation(libs.converter.kotlinx.serialization)
     implementation(libs.okhttp)
     debugImplementation(libs.logging.interceptor)
 
@@ -163,7 +164,7 @@ dependencies {
     implementation(libs.androidx.biometric)
 
     // JSON
-    implementation(libs.gson)
+    implementation(libs.kotlinx.serialization.json)
 
     // icons
     implementation(libs.androidx.material.icons.extended)