Audit 9a.3: custom sheets → ModalBottomSheet (M3 parity)

CompletionHistorySheet + contractor-picker sheet now use
material3.ModalBottomSheet. Standard Material 3 dim-behind + swipe-down
dismiss + sheet state. Inner content unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

composeApp/src/commonMain/kotlin/com/tt/honeyDue/ui/components/task/CompletionHistorySheet.kt

@@ -53,11 +53,10 @@ fun CompletionHistorySheet(
         }
     }
 
+    val sheetState = rememberModalBottomSheetState()
     ModalBottomSheet(
         onDismissRequest = onDismiss,
-        sheetState = rememberModalBottomSheetState(skipPartiallyExpanded = false),
+        sheetState = sheetState,
-        containerColor = MaterialTheme.colorScheme.surface,
-        dragHandle = { BottomSheetDefaults.DragHandle() }
     ) {
         Column(
             modifier = Modifier