chore: refactor UI components to align with design system tokens

apps/mobile/packages/features/client/billing/lib/src/presentation/widgets/payment_method_card.dart

@@ -1,7 +1,7 @@
 import 'package:core_localization/core_localization.dart';
 import 'package:design_system/design_system.dart';
-import 'package:flutter/material.dart';
 import 'package:firebase_data_connect/firebase_data_connect.dart' as fdc;
+import 'package:flutter/material.dart';
 import 'package:krow_data_connect/krow_data_connect.dart' as dc;
 
 /// Card showing the current payment method.
@@ -131,8 +131,9 @@ class _PaymentMethodCardState extends State<PaymentMethodCard> {
                         ),
                         if (isPrimary)
                           Container(
-                              horizontal: UiConstants.space1 + 2,
-                              vertical: UiConstants.space0 + 2,
+                            padding: const EdgeInsets.symmetric(
+                              horizontal: UiConstants.space2,
+                              vertical: UiConstants.space1,
                             ),
                             decoration: BoxDecoration(
                               color: UiColors.accent,

apps/mobile/packages/features/client/home/lib/src/presentation/widgets/shift_order_form_sheet.dart

@@ -767,7 +767,7 @@ class _ShiftOrderFormSheetState extends State<ShiftOrderFormSheet> {
   Widget _buildHeader() {
     return Container(
       padding: const EdgeInsets.all(UiConstants.space5),
-      decoration: const BoxDecoration(
+      decoration: BoxDecoration(
         gradient: LinearGradient(
           begin: Alignment.topLeft,
           end: Alignment.bottomRight,

apps/mobile/packages/features/client/view_orders/lib/src/presentation/widgets/view_order_card.dart

@@ -1439,11 +1439,11 @@ class _OrderEditSheetState extends State<_OrderEditSheet> {
                         minimumSize: Size.zero,
                         tapTargetSize: MaterialTapTargetSize.shrinkWrap,
                       ),
-                      child: const Row(
+                      child: Row(
                         mainAxisSize: MainAxisSize.min,
+                        spacing: UiConstants.space2,
                         children: <Widget>[
-                          Icon(UiIcons.add, size: 16, color: UiColors.primary),
-                          SizedBox(width: UiConstants.space2),
+                          const Icon(UiIcons.add, size: 16, color: UiColors.primary),
                           Text(
                             'Add Position',
                             style: UiTypography.body2m.primary,