fix(install): make the sheet look like a sheet

Bottom-sheet style was a dialog card moved to the bottom edge: same
AlertDialog container colour, same drop shadow, same dialog shape. It read as
a lowered dialog because that is all it was.

Now it takes the Material 3 sheet treatment — sheet container colour, no drop
shadow, expanded sheet shape — plus a drag handle to grab and
navigationBarsPadding so the action row is not sitting on the gesture bar.
That last part follows InstallerX Revived's sheet, whose own action row
carries navigationBarsPadding with extra bottom padding under gesture
navigation.

The stage content is still shared with the dialog style; only the container
differs, which was the point of splitting them.

Verified on device by opening an APK from ZArchiver with the sheet style on.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: nqmgaming

app/src/main/java/app/pwhs/universalinstaller/presentation/install/DialogInstallActivity.kt

@@ -47,12 +47,15 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.navigationBarsPadding
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.systemBars
 import androidx.compose.foundation.layout.widthIn
 import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.material3.AlertDialogDefaults
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.BottomSheetDefaults
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
@@ -132,6 +135,7 @@ import androidx.compose.foundation.isSystemInDarkTheme
  * - Cancel button → same.
  * - Install button → starts install; dialog shows progress then result.
  */
+@OptIn(ExperimentalMaterial3Api::class)
 class DialogInstallActivity : ComponentActivity() {
 
     private val viewModel: InstallViewModel by viewModel()
@@ -183,6 +187,32 @@ class DialogInstallActivity : ComponentActivity() {
     /** Track whether system took us to a confirmation activity. */
     private var wentToSystemConfirm = false
 
+    /**
+     * The parts that make a sheet a sheet rather than a lowered dialog: a drag handle to grab, and
+     * content kept clear of the gesture bar so the action row is not sitting on the system inset.
+     *
+     * Mirrors what InstallerX Revived's sheet does — its own action row carries
+     * `navigationBarsPadding()` plus extra bottom padding under gesture navigation.
+     */
+    @OptIn(ExperimentalMaterial3Api::class)
+    @Composable
+    private fun SheetChrome(enabled: Boolean, content: @Composable () -> Unit) {
+        if (!enabled) {
+            content()
+            return
+        }
+        Column(
+            modifier = Modifier
+                .fillMaxWidth()
+                .navigationBarsPadding()
+                .padding(bottom = 8.dp),
+            horizontalAlignment = Alignment.CenterHorizontally,
+        ) {
+            BottomSheetDefaults.DragHandle()
+            content()
+        }
+    }
+
     /**
      * Slides the sheet up on first composition. The dialog style is left untouched — it already
      * arrives with the activity's own window animation, and a second one on top reads as a stutter.
@@ -617,11 +647,15 @@ class DialogInstallActivity : ComponentActivity() {
                             .pointerInput(Unit) {
                                 detectTapGestures(onTap = { /* consume clicks */ })
                             },
-                        shape = if (isSheet) SHEET_SHAPE else AlertDialogDefaults.shape,
-                        color = AlertDialogDefaults.containerColor,
-                        tonalElevation = AlertDialogDefaults.TonalElevation,
-                        shadowElevation = 12.dp,
+                        // A sheet is attached to the edge, not floating over the screen: it takes
+                        // the sheet container colour and no drop shadow. Lowering a dialog card to
+                        // the bottom without this still reads as a dialog.
+                        shape = if (isSheet) BottomSheetDefaults.ExpandedShape else AlertDialogDefaults.shape,
+                        color = if (isSheet) BottomSheetDefaults.ContainerColor else AlertDialogDefaults.containerColor,
+                        tonalElevation = if (isSheet) BottomSheetDefaults.Elevation else AlertDialogDefaults.TonalElevation,
+                        shadowElevation = if (isSheet) 0.dp else 12.dp,
                     ) {
+                      SheetChrome(enabled = isSheet) {
                         val params = generateDialogParams(
                             uiState = uiState,
                             dialogTarget = dialogTarget,
@@ -701,6 +735,7 @@ class DialogInstallActivity : ComponentActivity() {
                             centerContent = dialogInnerWidget(params.content),
                             centerButton = dialogInnerWidget(params.buttons)
                         )
+                      }
                     }
                   }
                 }