feat(billing): integrate Stripe for subscription management and billing access

- Added billing-related fields to the User model in the database.
- Implemented functions for managing billing access, including trial periods and subscription statuses.
- Created new billing utility functions for Stripe integration.
- Updated onboarding page to include billing overview and workspace creation eligibility.
- Enhanced route access checks to require billing access for certain actions.
- Implemented cleanup scripts for expired billing workspaces and associated media.
- Updated header component to conditionally show app navigation based on billing access.
- Added new migrations for billing-related database changes.

app/api/stripe/webhook/route.ts

@@ -0,0 +1,88 @@
+import { NextRequest } from 'next/server';
+import type Stripe from 'stripe';
+import {
+  markSubscriptionCanceledByCustomerId,
+  syncStripeSubscriptionToUser,
+} from '@/lib/billing';
+import { getStripe, getStripeWebhookSecret } from '@/lib/stripe';
+
+export const runtime = 'nodejs';
+
+async function handleSubscriptionDeleted(subscription: Stripe.Subscription) {
+  const customerId =
+    typeof subscription.customer === 'string'
+      ? subscription.customer
+      : subscription.customer.id;
+
+  const currentPeriodEnd =
+    'current_period_end' in subscription && typeof subscription.current_period_end === 'number'
+      ? new Date(subscription.current_period_end * 1000)
+      : null;
+  const endedAt =
+    'ended_at' in subscription && typeof subscription.ended_at === 'number'
+      ? new Date(subscription.ended_at * 1000)
+      : currentPeriodEnd;
+
+  await markSubscriptionCanceledByCustomerId(customerId, {
+    currentPeriodEnd,
+    endedAt,
+  });
+}
+
+export async function POST(request: NextRequest) {
+  const signature = request.headers.get('stripe-signature');
+  if (!signature) {
+    return new Response('Missing Stripe signature', { status: 400 });
+  }
+
+  let event: Stripe.Event;
+
+  try {
+    const stripe = getStripe();
+    const body = await request.text();
+    event = stripe.webhooks.constructEvent(body, signature, getStripeWebhookSecret());
+  } catch (error) {
+    console.error('Failed to verify Stripe webhook:', error);
+    return new Response('Invalid webhook signature', { status: 400 });
+  }
+
+  try {
+    const stripe = getStripe();
+
+    switch (event.type) {
+      case 'checkout.session.completed': {
+        const session = event.data.object as Stripe.Checkout.Session;
+        if (session.mode === 'subscription' && session.subscription) {
+          const subscriptionId =
+            typeof session.subscription === 'string'
+              ? session.subscription
+              : session.subscription.id;
+          const subscription = await stripe.subscriptions.retrieve(subscriptionId);
+          await syncStripeSubscriptionToUser(subscription);
+        }
+        break;
+      }
+      case 'customer.subscription.created':
+      case 'customer.subscription.updated': {
+        const subscription = event.data.object as Stripe.Subscription;
+        await syncStripeSubscriptionToUser(subscription);
+        break;
+      }
+      case 'customer.subscription.deleted': {
+        const subscription = event.data.object as Stripe.Subscription;
+        await handleSubscriptionDeleted(subscription);
+        break;
+      }
+      default:
+        break;
+    }
+
+    return new Response(JSON.stringify({ received: true }), {
+      status: 200,
+      headers: { 'Content-Type': 'application/json' },
+    });
+  } catch (error) {
+    console.error('Failed to process Stripe webhook:', error);
+    return new Response('Webhook processing failed', { status: 500 });
+  }
+}