B2B-88: add starter kit structure and elements

app/home/[account]/billing/_lib/schema/team-billing.schema.ts

@@ -0,0 +1,13 @@
+import { z } from 'zod';
+
+export const TeamBillingPortalSchema = z.object({
+  accountId: z.string().uuid(),
+  slug: z.string().min(1),
+});
+
+export const TeamCheckoutSchema = z.object({
+  slug: z.string().min(1),
+  productId: z.string().min(1),
+  planId: z.string().min(1),
+  accountId: z.string().uuid(),
+});