feat(api-contract): add customer contract

Add customer contract with CRUD operations (list, get, create, update, delete).
Uses singular naming convention.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: npslaney

src/contracts/customer.ts

@@ -0,0 +1,56 @@
+import { oc } from "@orpc/contract";
+import { z } from "zod";
+import { CustomerSchema } from "../schemas/customer";
+import {
+	PaginationInputSchema,
+	PaginationOutputSchema,
+} from "../schemas/pagination";
+
+const ListCustomersInputSchema = PaginationInputSchema;
+const ListCustomersOutputSchema = PaginationOutputSchema.extend({
+	customers: z.array(CustomerSchema),
+});
+
+const GetCustomerInputSchema = z.object({ id: z.string() });
+
+const CreateCustomerInputSchema = z.object({
+	name: z.string().min(1),
+	email: z.string().email(),
+});
+
+const UpdateCustomerInputSchema = z.object({
+	id: z.string(),
+	name: z.string().optional(),
+	email: z.string().email().optional(),
+	userMetadata: z.record(z.string(), z.string()).optional(),
+});
+
+const DeleteCustomerInputSchema = z.object({ id: z.string() });
+
+export const listCustomersContract = oc
+	.input(ListCustomersInputSchema)
+	.output(ListCustomersOutputSchema);
+
+export const getCustomerContract = oc
+	.input(GetCustomerInputSchema)
+	.output(CustomerSchema);
+
+export const createCustomerContract = oc
+	.input(CreateCustomerInputSchema)
+	.output(CustomerSchema);
+
+export const updateCustomerContract = oc
+	.input(UpdateCustomerInputSchema)
+	.output(CustomerSchema);
+
+export const deleteCustomerContract = oc
+	.input(DeleteCustomerInputSchema)
+	.output(z.object({ ok: z.literal(true) }));
+
+export const customer = {
+	list: listCustomersContract,
+	get: getCustomerContract,
+	create: createCustomerContract,
+	update: updateCustomerContract,
+	delete: deleteCustomerContract,
+};

src/index.ts

@@ -1,4 +1,5 @@
 import { checkout } from "./contracts/checkout";
+import { customer } from "./contracts/customer";
 import {
 	checkouts as mcpCheckouts,
 	customers as mcpCustomers,
@@ -58,7 +59,7 @@ export {
 } from "./schemas/product-price-input";
 
 // SDK contract - consumed by SDK clients
-export const contract = { checkout, onboarding, products };
+export const contract = { checkout, customer, onboarding, products };
 
 /**
  * MCP contract - separate namespace for MCP tools.