Add MainActivity scaffold anchoring.

app/src/main/java/org/thoughtcrime/securesms/MainActivity.kt

@@ -37,6 +37,7 @@ import androidx.compose.foundation.layout.systemBarsPadding
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.SnackbarDuration
 import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
+import androidx.compose.material3.adaptive.layout.PaneExpansionAnchor
 import androidx.compose.material3.adaptive.layout.rememberPaneExpansionState
 import androidx.compose.material3.adaptive.navigation.ThreePaneScaffoldNavigator
 import androidx.compose.runtime.Composable
@@ -50,6 +51,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
 import androidx.fragment.app.DialogFragment
 import androidx.fragment.compose.AndroidFragment
 import androidx.fragment.compose.rememberFragmentState
@@ -329,7 +331,15 @@ class MainActivity : PassphraseRequiredActivity(), VoiceNoteMediaControllerOwner
 
       MainContainer {
         val wrappedNavigator = rememberNavigator(windowSizeClass, contentLayoutData, maxWidth)
-        val paneExpansionState = rememberPaneExpansionState()
+        val listPaneWidth = contentLayoutData.rememberDefaultPanePreferredWidth(maxWidth)
+        val halfPartitionWidth = contentLayoutData.partitionWidth / 2
+        val paneExpansionState = rememberPaneExpansionState(
+          anchors = listOf(
+            PaneExpansionAnchor.Offset.fromStart(72.dp + contentLayoutData.listPaddingStart + halfPartitionWidth),
+            PaneExpansionAnchor.Offset.fromStart(listPaneWidth + halfPartitionWidth),
+            PaneExpansionAnchor.Offset.fromEnd(contentLayoutData.detailPaddingEnd - halfPartitionWidth)
+          )
+        )
         val mutableInteractionSource = remember { MutableInteractionSource() }
 
         AppScaffold(

app/src/main/java/org/thoughtcrime/securesms/util/RemoteConfig.kt

@@ -535,7 +535,7 @@ object RemoteConfig {
     key = "android.internalUser",
     hotSwappable = true
   ) { value ->
-     value.asBoolean(false) || Environment.IS_NIGHTLY || Environment.IS_STAGING
+    value.asBoolean(false) || Environment.IS_NIGHTLY || Environment.IS_STAGING
   }
 
   /** The raw client expiration JSON string.  */

app/src/main/java/org/thoughtcrime/securesms/window/AppScaffold.kt

@@ -219,7 +219,7 @@ fun AppScaffold(
     return
   }
 
-  val minPaneWidth = 300.dp
+  val minPaneWidth = navigator.scaffoldDirective.defaultPanePreferredWidth
 
   NavigableListDetailPaneScaffold(
     navigator = navigator,