feat: migrate from lemonsqueezy to polar (#535)

* feat: move from lemonsqueezy to polar

* update lock

* add migration files

* test with demo product id

apps/dashboard/src/routes/api/polar/subscribe/+server.ts

@@ -0,0 +1,14 @@
+import { env } from '$env/dynamic/private';
+import { Checkout } from 'polar-sveltekit';
+
+export const GET = ({ ...params }) => {
+  const metadata = JSON.parse(params.url.searchParams.get('metadata') ?? '{}');
+  const successUrl = `/org/${metadata.orgSlug}?upgrade=true&confirmation=true`;
+
+  const request = Checkout({
+    accessToken: env.POLAR_ACCESS_TOKEN,
+    successUrl
+  });
+
+  return request(params);
+};