moved billing types to shared package

shared/models/billingModels/context/attachBillingContext.ts

@@ -0,0 +1,30 @@
+import type { FullCusProduct, FullProduct } from "@autumn/shared";
+import { z } from "zod/v4";
+import type { BillingContext } from "./billingContext";
+
+// Plan timing for attach operations
+export const PlanTimingSchema = z.enum(["immediate", "end_of_cycle"]);
+export type PlanTiming = z.infer<typeof PlanTimingSchema>;
+
+// Checkout mode for attach operations
+export const CheckoutModeSchema = z
+	.enum(["stripe_checkout", "autumn_checkout"])
+	.nullable();
+
+export type CheckoutMode = z.infer<typeof CheckoutModeSchema>;
+
+export interface AttachBillingContext extends BillingContext {
+	// The product being attached
+	attachProduct: FullProduct;
+
+	// Transition context (only for main recurring products)
+	currentCustomerProduct?: FullCusProduct; // To transition from
+	scheduledCustomerProduct?: FullCusProduct; // To delete
+
+	// Timing
+	planTiming: PlanTiming;
+	endOfCycleMs?: number; // Only needed if planTiming === "end_of_cycle"
+
+	// Checkout
+	checkoutMode: CheckoutMode;
+}