refactor: update company registration flow and email handling; switch to zod for validation

public/locales/et/common.json

@@ -92,5 +92,11 @@
     "description": "This website uses cookies to ensure you get the best experience on our website.",
     "reject": "Reject",
     "accept": "Accept"
+  },
+  "formField": {
+    "companyName": "Ettevõtte nimi",
+    "contactPerson": "Kontaktisik",
+    "email": "E-mail",
+    "phone": "Telefon"
   }
 }