fix: company save — cast int fields, fix error redirect URL

- Cast erp_active_users (and requires_approval, is_active) to int
  before INSERT/UPDATE so empty string '' doesn't fail the INT column
- Fix error redirect for new company: was /admin/companies/new (404),
  now /admin/company/edit (the actual new-company route)

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

services/CompanyRepository.php

@@ -50,6 +50,13 @@ class CompanyRepository
             }
         }
 
+        // Integer fields: cast so empty string '' doesn't fail the INT column
+        foreach (['requires_approval', 'is_active', 'erp_active_users'] as $f) {
+            if (array_key_exists($f, $data)) {
+                $data[$f] = (int)$data[$f];
+            }
+        }
+
         $params = [];
         $sets   = [];
         foreach ($fields as $f) {