feat(i18n): localize recipient validation messages

tests/unit/actions/recipient.messages.test.ts

@@ -0,0 +1,38 @@
+import { describe, expect, it } from "vitest"
+
+import { localizeRecipientFieldErrors } from "@/actions/recipient.messages"
+
+const actionCopy = {
+  createSuccess: "Destinatario creado correctamente",
+  createFailure: "Error al crear el destinatario",
+  updateSuccess: "Destinatario actualizado correctamente",
+  updateFailure: "Error al actualizar el destinatario",
+  duplicateUsername: "El nombre de usuario ya existe",
+  duplicateEmail: "El correo electrónico ya existe",
+}
+
+describe("recipient action message localization", () => {
+  it("localizes known recipient field errors", () => {
+    expect(
+      localizeRecipientFieldErrors(
+        {
+          username: ["Username already exists"],
+          email: ["Email already exists"],
+        },
+        actionCopy,
+      ),
+    ).toEqual({
+      username: [actionCopy.duplicateUsername],
+      email: [actionCopy.duplicateEmail],
+    })
+  })
+
+  it("keeps unknown messages unchanged", () => {
+    expect(
+      localizeRecipientFieldErrors(
+        { username: ["Unexpected recipient issue"] },
+        actionCopy,
+      ),
+    ).toEqual({ username: ["Unexpected recipient issue"] })
+  })
+})