some backend fixes and add android app

android/gradle/libs.versions.toml

@@ -0,0 +1,49 @@
+[versions]
+agp = "9.4.1"
+kotlin = "2.4.21"
+# compileSdk 37 because Compose 1.12 (BOM 2026.09.00) requires it; the platform is
+# published under the new minor-version scheme as `platforms;android-37.0`.
+# targetSdk stays 36 — Android 16 is what the Nothing Phone (3) runs, and opting into
+# a newer runtime's behaviour changes is a separate decision from compiling against it.
+compileSdk = "37"
+targetSdk = "36"
+minSdk = "34"
+composeBom = "2026.09.00"
+activityCompose = "1.13.0"
+navigationCompose = "2.10.2"
+lifecycle = "2.11.0"
+coroutines = "1.10.2"
+robolectric = "4.14.1"
+serialization = "1.11.0"
+okhttp = "5.5.0"
+junit = "4.13.2"
+
+[libraries]
+kotlin-test = { module = "org.jetbrains.kotlin:kotlin-test", version.ref = "kotlin" }
+junit = { module = "junit:junit", version.ref = "junit" }
+robolectric = { module = "org.robolectric:robolectric", version.ref = "robolectric" }
+coroutines-test = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-test", version.ref = "coroutines" }
+serialization-json = { module = "org.jetbrains.kotlinx:kotlinx-serialization-json", version.ref = "serialization" }
+okhttp = { module = "com.squareup.okhttp3:okhttp", version.ref = "okhttp" }
+mockwebserver = { module = "com.squareup.okhttp3:mockwebserver3-junit4", version.ref = "okhttp" }
+
+compose-bom = { module = "androidx.compose:compose-bom", version.ref = "composeBom" }
+compose-ui = { module = "androidx.compose.ui:ui" }
+compose-ui-graphics = { module = "androidx.compose.ui:ui-graphics" }
+compose-ui-tooling = { module = "androidx.compose.ui:ui-tooling" }
+compose-ui-tooling-preview = { module = "androidx.compose.ui:ui-tooling-preview" }
+compose-ui-test-junit4 = { module = "androidx.compose.ui:ui-test-junit4" }
+compose-ui-test-manifest = { module = "androidx.compose.ui:ui-test-manifest" }
+compose-foundation = { module = "androidx.compose.foundation:foundation" }
+compose-material3 = { module = "androidx.compose.material3:material3" }
+
+activity-compose = { module = "androidx.activity:activity-compose", version.ref = "activityCompose" }
+navigation-compose = { module = "androidx.navigation:navigation-compose", version.ref = "navigationCompose" }
+lifecycle-viewmodel-compose = { module = "androidx.lifecycle:lifecycle-viewmodel-compose", version.ref = "lifecycle" }
+lifecycle-runtime-compose = { module = "androidx.lifecycle:lifecycle-runtime-compose", version.ref = "lifecycle" }
+
+[plugins]
+kotlin-jvm = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
+android-application = { id = "com.android.application", version.ref = "agp" }
+kotlin-compose = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlin" }
+kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }