fix(webapp): stop rejecting card requests for customers with no identifier

A contact created by an integration can legitimately have neither an email nor an
external id. The schema still rejected that shape, so Plain recorded an
integration error for the whole request — the same failure this PR removes for a
null external id.

There is nothing to look up, so the route now answers every requested key with no
data and Plain hides the cards. The route already handled it; only the refine
stood in the way.

Author: isshaddad

apps/webapp/app/utils/plainCustomerCards.test.ts

@@ -44,12 +44,14 @@ describe("PlainCustomerCardRequestSchema", () => {
     expect(PlainCustomerCardRequestSchema.safeParse(request()).success).toBe(true);
   });
 
-  it("still requires one of email or externalId", () => {
+  // A contact created by an integration can have neither identifier. There's nothing to look up,
+  // but rejecting it would make Plain record an integration error rather than hide the card.
+  it("accepts a customer with neither email nor externalId", () => {
     const result = PlainCustomerCardRequestSchema.safeParse(
       request({ customer: { id: "c_1", email: null, externalId: null } })
     );
 
-    expect(result.success).toBe(false);
+    expect(result.success).toBe(true);
   });
 
   it("rejects a body with no card keys field", () => {

apps/webapp/app/utils/plainCustomerCards.ts

@@ -11,16 +11,15 @@ import { z } from "zod";
  */
 export const PlainCustomerCardRequestSchema = z.object({
   cardKeys: z.array(z.string()),
-  customer: z
-    .object({
-      id: z.string(),
-      email: z.string().nullish(),
-      externalId: z.string().nullish(),
-    })
-    .refine((data) => data.email || data.externalId, {
-      message: "Either customer.email or customer.externalId must be provided",
-      path: ["customer"],
-    }),
+  // A customer with neither an email nor an external id is valid input, not a malformed request:
+  // a contact created by an integration can legitimately have neither. There's nothing to look up,
+  // so the route answers every key with no data — rejecting it would make Plain record an
+  // integration error, which is the failure this schema change exists to remove.
+  customer: z.object({
+    id: z.string(),
+    email: z.string().nullish(),
+    externalId: z.string().nullish(),
+  }),
   thread: z
     .object({
       id: z.string(),