feat: add free tier Stripe subscription

apps/web/src/app/(dashboard)/settings/billing/billing-portal-button.tsx

@@ -0,0 +1,54 @@
+'use client';
+
+import { useState } from 'react';
+
+import { Button } from '@documenso/ui/primitives/button';
+import { useToast } from '@documenso/ui/primitives/use-toast';
+
+import { createBillingPortal } from './create-billing-portal.action';
+
+export default function BillingPortalButton() {
+  const { toast } = useToast();
+
+  const [isFetchingPortalUrl, setIsFetchingPortalUrl] = useState(false);
+
+  const handleFetchPortalUrl = async () => {
+    if (isFetchingPortalUrl) {
+      return;
+    }
+
+    setIsFetchingPortalUrl(true);
+
+    try {
+      const sessionUrl = await createBillingPortal();
+      if (!sessionUrl) {
+        throw new Error('NO_SESSION');
+      }
+
+      window.open(sessionUrl, '_blank');
+    } catch (e) {
+      let description =
+        'We are unable to proceed to the billing portal at this time. Please try again, or contact support.';
+
+      if (e.message === 'CUSTOMER_NOT_FOUND') {
+        description =
+          'You do not currently have a customer record, this should not happen. Please contact support for assistance.';
+      }
+
+      toast({
+        title: 'Something went wrong',
+        description,
+        variant: 'destructive',
+        duration: 10000,
+      });
+    }
+
+    setIsFetchingPortalUrl(false);
+  };
+
+  return (
+    <Button onClick={async () => handleFetchPortalUrl()} loading={isFetchingPortalUrl}>
+      Manage Subscription
+    </Button>
+  );
+}