style: improve list layout — larger fonts, adjusted column widths, center alignment

Boxing number module:
- Data row base font size 12→15, quantity column / edit mode unified to 15
- Work order column width flex 24→30, quantity column flex 14→23, action column 64px→54px
- Multi-code boxing total row column width flex 22→26
- Center-align all table headers and data rows

Shelf registration module:
- Data row base font size 12→15
- Center-align all table headers and data rows (location number changed from right-align to center)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/pages/registration_page.dart

@@ -1018,8 +1018,8 @@ class _RegistrationPageState extends State<RegistrationPage> {
       ),
       child: const Row(
         children: [
-          Expanded(flex: 22, child: Text('总排号', style: _headerStyle)),
-          Expanded(flex: 18, child: Text('工令号', style: _headerStyle)),
+          Expanded(flex: 22, child: Text('总排号', textAlign: TextAlign.center, style: _headerStyle)),
+          Expanded(flex: 18, child: Text('工令号', textAlign: TextAlign.center, style: _headerStyle)),
           Expanded(
             flex: 12,
             child: Text(
@@ -1032,7 +1032,7 @@ class _RegistrationPageState extends State<RegistrationPage> {
             flex: 28,
             child: Text(
               '货位号',
-              textAlign: TextAlign.right,
+              textAlign: TextAlign.center,
               style: _headerStyle,
             ),
           ),
@@ -1148,7 +1148,7 @@ class _RegistrationPageState extends State<RegistrationPage> {
 
   Widget _buildListRow(PaichaOverviewItem item, {required bool isScanned}) {
     final rowStyle = TextStyle(
-      fontSize: 12,
+      fontSize: 15,
       fontWeight: isScanned ? FontWeight.w700 : FontWeight.w500,
       color: Colors.black87,
     );
@@ -1185,6 +1185,7 @@ class _RegistrationPageState extends State<RegistrationPage> {
             flex: 22,
             child: Text(
               item.zongpaiNo,
+              textAlign: TextAlign.center,
               overflow: TextOverflow.ellipsis,
               style: rowStyle,
             ),
@@ -1193,6 +1194,7 @@ class _RegistrationPageState extends State<RegistrationPage> {
             flex: 18,
             child: Text(
               item.workOrderNo ?? '--',
+              textAlign: TextAlign.center,
               overflow: TextOverflow.ellipsis,
               style: rowStyle,
             ),
@@ -1210,7 +1212,7 @@ class _RegistrationPageState extends State<RegistrationPage> {
             flex: 28,
             child: Text(
               item.locationCode ?? '\u2014',
-              textAlign: TextAlign.right,
+              textAlign: TextAlign.center,
               overflow: TextOverflow.ellipsis,
               style: rowStyle,
             ),