Fix company TIN field mapping in payload

frontend/src/pages/companies/CompaniesPage.tsx

@@ -37,7 +37,11 @@ export const CompaniesPage = () => {
     const handleCreateCompany = async (e: React.FormEvent) => {
         e.preventDefault();
         try {
-            await apiClient.post('/companies', { name, tin, address });
+            await apiClient.post('/companies', { 
+                name, 
+                tax_identification_number: tin, 
+                address 
+            });
             setIsAddModalOpen(false);
             setName('');
             setTin('');
@@ -50,7 +54,7 @@ export const CompaniesPage = () => {
     };
 
     const filteredCompanies = companies.filter(c => 
-        c.name.includes(searchTerm) || c.tin?.includes(searchTerm)
+        c.name.includes(searchTerm) || c.tax_identification_number?.includes(searchTerm)
     );
 
     return (
@@ -113,7 +117,7 @@ export const CompaniesPage = () => {
                                 </button>
                             </div>
                             <h3 className="text-xl font-bold text-slate-900 mb-1">{company.name}</h3>
-                            <p className="text-sm text-slate-500 mb-6">الرقم الضريبي: <span className="font-mono font-bold text-slate-700">{company.tin || 'غير محدد'}</span></p>
+                            <p className="text-sm text-slate-500 mb-6">الرقم الضريبي: <span className="font-mono font-bold text-slate-700">{company.tax_identification_number || 'غير محدد'}</span></p>
                             
                             <div className="pt-4 border-t border-slate-100 flex items-center justify-between">
                                 <div className="flex items-center gap-2 text-xs font-bold text-slate-500">