Fix internal navigation links: add /kitchen/ prefix to all bare hrefs

Bare <a href="/invoice/..."> tags bypass React Router basename, causing
hard navigations to absolute paths with no NPM route. Added /kitchen/
prefix to all internal href values across 12 components.

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

frontend/src/components/GPReport.tsx

@@ -989,7 +989,7 @@ export default function GPReport() {
         <div style={{ ...styles.breakdownContainer, textAlign: 'center', marginBottom: '1.5rem' }}>
           <h3 style={styles.sectionTitle}>Top Sellers</h3>
           <p style={{ color: '#666', margin: '2rem 0' }}>
-            No categories configured. <a href="/sambapos" style={{ color: '#e94560' }}>Configure SambaPOS categories</a> to see top sellers by category.
+            No categories configured. <a href="/kitchen/sambapos" style={{ color: '#e94560' }}>Configure SambaPOS categories</a> to see top sellers by category.
           </p>
         </div>
       ) : (

frontend/src/components/InvoiceList.tsx

@@ -161,7 +161,7 @@ export default function InvoiceList() {
     <div>
       <div style={styles.header}>
         <h2 style={styles.title}>Uploaded Invoices</h2>
-        <a href="/upload" style={styles.uploadBtn}>
+        <a href="/kitchen/upload" style={styles.uploadBtn}>
           + Upload New
         </a>
       </div>
@@ -226,7 +226,7 @@ export default function InvoiceList() {
       {invoices.length === 0 ? (
         <div style={styles.empty}>
           <p>No invoices pending confirmation.</p>
-          <a href="/upload" style={styles.link}>
+          <a href="/kitchen/upload" style={styles.link}>
             Upload one now
           </a>
         </div>
@@ -235,7 +235,7 @@ export default function InvoiceList() {
           {invoices.map((invoice) => (
             <a
               key={invoice.id}
-              href={`/invoice/${invoice.id}`}
+              href={`/kitchen/invoice/${invoice.id}`}
               style={{
                 ...styles.card,
                 borderLeft: `4px solid ${statusColors[invoice.status] || '#999'}`,
@@ -341,7 +341,7 @@ export default function InvoiceList() {
             {completedInvoices.map((invoice) => (
               <a
                 key={invoice.id}
-                href={`/invoice/${invoice.id}`}
+                href={`/kitchen/invoice/${invoice.id}`}
                 style={{
                   ...styles.card,
                   borderLeft: `4px solid ${statusColors[invoice.status] || '#999'}`,

frontend/src/components/LineItemHistoryModal.tsx

@@ -388,7 +388,7 @@ export default function LineItemHistoryModal({
                                     {data.description || '-'}
                                   </span>
                                   <a
-                                    href={`/invoice/${point.invoice_id}`}
+                                    href={`/kitchen/invoice/${point.invoice_id}`}
                                     target="_blank"
                                     rel="noopener noreferrer"
                                     style={{

frontend/src/components/SearchDefinitions.tsx

@@ -617,7 +617,7 @@ export default function SearchDefinitions() {
                     <td style={tdStyle}>
                       {def.source_invoice_number ? (
                         <a
-                          href={`/invoice/${def.source_invoice_id}`}
+                          href={`/kitchen/invoice/${def.source_invoice_id}`}
                           target="_blank"
                           rel="noopener noreferrer"
                           style={{ color: '#2563eb', textDecoration: 'none' }}
@@ -692,7 +692,7 @@ export default function SearchDefinitions() {
                 <div>
                   <strong>Source Invoice:</strong>{' '}
                   <a
-                    href={`/invoice/${editingDef.source_invoice_id}`}
+                    href={`/kitchen/invoice/${editingDef.source_invoice_id}`}
                     target="_blank"
                     rel="noopener noreferrer"
                     style={{ color: '#2563eb' }}

frontend/src/components/SearchInvoices.tsx

@@ -415,7 +415,7 @@ export default function SearchInvoices() {
                           <tr key={inv.id} style={{ borderBottom: '1px solid #e5e7eb' }}>
                             <td style={tdStyle}>
                               <a
-                                href={`/invoice/${inv.id}`}
+                                href={`/kitchen/invoice/${inv.id}`}
                                 target="_blank"
                                 rel="noopener noreferrer"
                                 style={{ color: '#2563eb', textDecoration: 'none' }}
@@ -466,7 +466,7 @@ export default function SearchInvoices() {
                   <tr key={inv.id} style={{ borderBottom: '1px solid #e5e7eb' }}>
                     <td style={tdStyle}>
                       <a
-                        href={`/invoice/${inv.id}`}
+                        href={`/kitchen/invoice/${inv.id}`}
                         target="_blank"
                         rel="noopener noreferrer"
                         style={{ color: '#2563eb', textDecoration: 'none' }}

frontend/src/components/Upload.tsx

@@ -502,7 +502,7 @@ export default function Upload() {
               Install App
             </button>
           ) : (
-            <a href="/upload-app" style={styles.openAppLink}>Open Upload App</a>
+            <a href="/kitchen/upload-app" style={styles.openAppLink}>Open Upload App</a>
           )}
         </div>
       </div>