app: use ShortNavigationBar and fix insets

- Replace Material 3 NavigationBar with ShortNavigationBar and
  ShortNavigationBarItem for a more compact bottom bar.
- Set contentWindowInsets to zero on the root Scaffold so status bar
  insets are passed down to child screens' TopAppBars.
- Consume innerPadding on HorizontalPager to prevent nested Scaffolds
  from duplicating bottom system navigation insets.

Assisted-by: Gemini 3.8 Flash

app/apk/src/main/java/com/topjohnwu/magisk/ui/MainScreen.kt

@@ -2,15 +2,16 @@ package com.topjohnwu.magisk.ui
 
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.LocalActivity
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.consumeWindowInsets
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.pager.HorizontalPager
 import androidx.compose.foundation.pager.rememberPagerState
 import androidx.compose.material3.Icon
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.NavigationBar
-import androidx.compose.material3.NavigationBarItem
 import androidx.compose.material3.Scaffold
+import androidx.compose.material3.ShortNavigationBar
+import androidx.compose.material3.ShortNavigationBarItem
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
@@ -72,12 +73,11 @@ fun MainScreen(
 
     Scaffold(
         modifier = modifier.fillMaxSize(),
+        contentWindowInsets = WindowInsets(0, 0, 0, 0),
         bottomBar = {
-            NavigationBar(
-                containerColor = MaterialTheme.colorScheme.surfaceContainer,
-            ) {
+            ShortNavigationBar {
                 visibleTabs.forEachIndexed { index, tab ->
-                    NavigationBarItem(
+                    ShortNavigationBarItem(
                         selected = pagerState.currentPage == index,
                         onClick = { scope.launch { pagerState.animateScrollToPage(index) } },
                         icon = {
@@ -96,7 +96,8 @@ fun MainScreen(
             state = pagerState,
             modifier = Modifier
                 .fillMaxSize()
-                .padding(bottom = innerPadding.calculateBottomPadding()),
+                .padding(innerPadding)
+                .consumeWindowInsets(innerPadding),
             beyondViewportPageCount = visibleTabs.size - 1,
             userScrollEnabled = true,
         ) { page ->