Refactor widgets & imports; add krow_domain

Add local krow_domain dependency to client, staff apps and client home package. Numerous UI/widget cleanups across features: add const where applicable, use explicit List<Widget> types and List<Widget>.generate, add super.key to constructors, tighten BlocProvider generics, replace some Containers with SizedBox, and simplify InputDecoration/Border constructors. Fix API error handler to return a const UnknownException. Update internal imports to package-style paths (staff_home, staff_payments, staff_main repository interface) and normalize Flutter imports (use material.dart). Add missing braces for early returns in tax form pages. Mostly formatting and small API/typing refactors with no behavioral changes intended.

apps/mobile/packages/features/staff/payments/lib/src/payments_module.dart

@@ -1,8 +1,7 @@
-import 'package:flutter/src/widgets/framework.dart';
+import 'package:flutter/material.dart';
 import 'package:flutter_modular/flutter_modular.dart';
 import 'package:krow_core/core.dart';
 import 'package:krow_domain/krow_domain.dart';
-
 import 'package:staff_payments/src/data/repositories/payments_repository_impl.dart';
 import 'package:staff_payments/src/domain/repositories/payments_repository.dart';
 import 'package:staff_payments/src/domain/usecases/get_payment_chart_usecase.dart';

apps/mobile/packages/features/staff/payments/lib/src/presentation/pages/early_pay_page.dart

@@ -27,7 +27,7 @@ class EarlyPayPage extends StatelessWidget {
                 border: Border.all(color: UiColors.primary.withValues(alpha: 0.1)),
               ),
               child: Column(
-                children: [
+                children: <Widget>[
                   Text(
                     context.t.staff_payments.early_pay.available_label,
                     style: UiTypography.body2m.textSecondary,
@@ -65,13 +65,13 @@ class EarlyPayPage extends StatelessWidget {
                 border: Border.all(color: UiColors.separatorPrimary),
               ),
               child: Row(
-                children: [
+                children: <Widget>[
                   const Icon(UiIcons.bank, size: 24, color: UiColors.primary),
                   const SizedBox(width: 12),
                   Expanded(
                     child: Column(
                       crossAxisAlignment: CrossAxisAlignment.start,
-                      children: [
+                      children: <Widget>[
                         Text('Chase Bank', style: UiTypography.body2b.textPrimary),
                         Text('Ending in 4321', style: UiTypography.footnote2r.textSecondary),
                       ],

apps/mobile/packages/features/staff/payments/lib/src/presentation/widgets/payments_page_skeleton/payment_item_skeleton.dart

@@ -18,13 +18,13 @@ class PaymentItemSkeleton extends StatelessWidget {
         borderRadius: UiConstants.radiusLg,
       ),
       child: const Row(
-        children: [
+        children: <Widget>[
           UiShimmerCircle(size: 40),
           SizedBox(width: UiConstants.space3),
           Expanded(
             child: Column(
               crossAxisAlignment: CrossAxisAlignment.start,
-              children: [
+              children: <Widget>[
                 UiShimmerLine(width: 140, height: 14),
                 SizedBox(height: UiConstants.space2),
                 UiShimmerLine(width: 100, height: 12),

apps/mobile/packages/features/staff/payments/lib/src/presentation/widgets/payments_page_skeleton/payments_page_skeleton.dart

@@ -16,12 +16,12 @@ class PaymentsPageSkeleton extends StatelessWidget {
     return UiShimmer(
       child: SingleChildScrollView(
         child: Column(
-          children: [
+          children: <Widget>[
             // Header section with gradient
             Container(
               decoration: BoxDecoration(
                 gradient: LinearGradient(
-                  colors: [
+                  colors: <Color>[
                     UiColors.primary,
                     UiColors.primary.withValues(alpha: 0.8),
                   ],
@@ -37,7 +37,7 @@ class PaymentsPageSkeleton extends StatelessWidget {
               ),
               child: Column(
                 crossAxisAlignment: CrossAxisAlignment.start,
-                children: [
+                children: <Widget>[
                   // Title placeholder
                   const UiShimmerLine(width: 120, height: 24),
                   const SizedBox(height: UiConstants.space6),
@@ -45,7 +45,7 @@ class PaymentsPageSkeleton extends StatelessWidget {
                   // Balance center
                   const Center(
                     child: Column(
-                      children: [
+                      children: <Widget>[
                         UiShimmerLine(width: 100, height: 14),
                         SizedBox(height: UiConstants.space1),
                         UiShimmerLine(width: 160, height: 36),
@@ -73,7 +73,7 @@ class PaymentsPageSkeleton extends StatelessWidget {
                 ),
                 child: Column(
                   crossAxisAlignment: CrossAxisAlignment.start,
-                  children: [
+                  children: <Widget>[
                     // Earnings graph placeholder
                     UiShimmerBox(
                       width: double.infinity,
@@ -83,10 +83,10 @@ class PaymentsPageSkeleton extends StatelessWidget {
                     const SizedBox(height: UiConstants.space6),
 
                     // Quick stats row
-                    Row(
-                      children: [
+                    const Row(
+                      children: <Widget>[
                         Expanded(child: UiShimmerStatsCard()),
-                        const SizedBox(width: UiConstants.space3),
+                        SizedBox(width: UiConstants.space3),
                         Expanded(child: UiShimmerStatsCard()),
                       ],
                     ),
@@ -99,7 +99,7 @@ class PaymentsPageSkeleton extends StatelessWidget {
                     // Payment history items
                     UiShimmerList(
                       itemCount: 4,
-                      itemBuilder: (index) => const PaymentItemSkeleton(),
+                      itemBuilder: (int index) => const PaymentItemSkeleton(),
                     ),
                   ],
                 ),