Add shared customer auth, cart handoff, and account dropdown.

Mirror Meshkee customer sessions onto the storefront, continue checkout on the customer dashboard, and show profile/orders/admin links under the header name.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/app/api/auth/register/route.ts

@@ -0,0 +1,36 @@
+import { DOMAIN } from "@/lib/meshkee";
+import { jsonResponse, meshkeeFetch } from "@/lib/meshkee-server";
+
+export async function POST(request: Request) {
+  const body = await request.json().catch(() => null);
+  if (
+    !body?.cellNumber ||
+    !body?.password ||
+    !body?.firstName ||
+    !body?.lastName
+  ) {
+    return jsonResponse({ error: "لطفاً همه فیلدهای الزامی را پر کنید" }, 400);
+  }
+
+  const res = await meshkeeFetch("/auth/register", {
+    method: "POST",
+    body: JSON.stringify({
+      cellNumber: body.cellNumber,
+      password: body.password,
+      firstName: body.firstName,
+      lastName: body.lastName,
+      email: body.email,
+      domain: DOMAIN,
+      acknowledgeExistingAccount: body.acknowledgeExistingAccount ?? false,
+    }),
+  });
+
+  if (!res.ok) {
+    return jsonResponse(
+      { error: "ثبت‌نام ناموفق بود. اطلاعات را بررسی کنید." },
+      res.status,
+    );
+  }
+
+  return jsonResponse(res.data, 201);
+}