[JetCaster] enable predictive back animations and add in pb NavHost animations (#1533)

Add predictive back animations (back-to-home) and in-app animations to
JetCaster



https://github.com/user-attachments/assets/3649450c-46a5-4c43-82f6-63ba9d4b4bbe

Author: trambui09

Jetcaster/mobile/src/main/AndroidManifest.xml

@@ -28,6 +28,7 @@
         android:label="@string/app_name"
         android:supportsRtl="true"
         android:theme="@style/Theme.Jetcaster"
+        android:enableOnBackInvokedCallback="true"
         android:usesCleartextTraffic="true">
 
         <activity

Jetcaster/mobile/src/main/java/com/example/jetcaster/ui/JetcasterApp.kt

@@ -16,6 +16,8 @@
 
 package com.example.jetcaster.ui
 
+import androidx.compose.animation.EnterTransition
+import androidx.compose.animation.scaleOut
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
@@ -40,7 +42,9 @@ fun JetcasterApp(
     if (appState.isOnline) {
         NavHost(
             navController = appState.navController,
-            startDestination = Screen.Home.route
+            startDestination = Screen.Home.route,
+            popExitTransition = { scaleOut(targetScale = 0.9f) },
+            popEnterTransition = { EnterTransition.None }
         ) {
             composable(Screen.Home.route) { backStackEntry ->
                 MainScreen(