fix(mobile): keep the settings pull-down in the body, not the sheet (#3324)

The settings page is a modal sheet whose body is one long verticalScroll. The
sheet also followed a pull-down, so a single gesture meant both "scroll the
body" and "drag the page away": on the emulator the same pull-down moves the
sheet 305 px and dismisses the page instead of scrolling the list.

AdaptiveModalSurface now takes `draggable` (default true, so every other sheet
keeps its current behaviour) and forwards it to Material's
`sheetGesturesEnabled`. Settings opts out; its close button, the back action,
and a tap on the scrim still close the page.

Author: wgqqqqq

src/apps/mobile/android/app/src/androidTest/kotlin/com/openbitfun/mobile/app/MobileScreenTest.kt

@@ -120,10 +120,9 @@ class MobileScreenTest {
     /**
      * The settings page closes by its own button.
      *
-     * The sheet has no drag handle — the source draws none, and the page centres
-     * its title where one would sit — so this button is the only way out that does
-     * not depend on guessing where a downward drag will be read as a dismissal
-     * rather than as a scroll. Losing it would strand the page.
+     * The page's body is one long scroll and the sheet does not take a pull-down,
+     * so a downward drag never dismisses it and this button is the exit that is
+     * always there. Losing it would strand the page.
      */
     @Test
     fun theSettingsPageClosesByItsOwnButton() {

src/apps/mobile/android/app/src/main/kotlin/com/openbitfun/mobile/app/ui/common/AdaptiveModalSurface.kt

@@ -47,6 +47,12 @@ import com.openbitfun.mobile.core.feature.layout.SettingsPlacementMode
  * placement uses a full-window Dialog so back handling, focus containment and
  * accessibility isolation remain native while the surface docks to the
  * physical trailing region selected by the shared policy.
+ *
+ * @param draggable whether the compact sheet follows a pull-down. A page whose
+ * body is itself a scroll should say no: the same pull-down then means both
+ * "scroll the body" and "drag the sheet away", so a gesture the user meant as
+ * scrolling can move the surface or dismiss the page. Such a page still closes
+ * through its own close button, the back action, and a tap on the scrim.
  */
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -56,6 +62,7 @@ internal fun AdaptiveModalSurface(
     onDismissRequest: () -> Unit,
     edgeToEdgeContent: Boolean = false,
     fitContent: Boolean = false,
+    draggable: Boolean = true,
     content: @Composable (Modifier) -> Unit,
 ) {
     if (!visible) return
@@ -137,6 +144,7 @@ internal fun AdaptiveModalSurface(
             topEnd = MobileDesignGeometry.SheetTopRadius,
         ),
         dragHandle = null,
+        sheetGesturesEnabled = draggable,
         contentWindowInsets = { if (edgeToEdgeContent) WindowInsets(0) else BottomSheetDefaults.windowInsets },
     ) {
         val modifier = if (fitContent) {

src/apps/mobile/android/app/src/main/kotlin/com/openbitfun/mobile/app/ui/shell/MobileScreen.kt

@@ -678,6 +678,10 @@ internal fun MobileScreen(onAccountRestored: (Boolean) -> Unit = {}) {
         visible = shell.showSettings,
         placement = settingsPlacement,
         onDismissRequest = shell::dismissSettings,
+        // The settings body is one long scroll, so a pull-down has to scroll it
+        // rather than drag the page away. The page closes through its own close
+        // button, the back action, and a tap on the scrim.
+        draggable = false,
         content = settingsContent,
     )
     AdaptiveModalSurface(