Add Stripe fee tracking on paid invoices + backfill function

- Store stripe_fee on invoices when webhook receives checkout.session.completed
- Display Stripe fee and net received in InvoiceDetail when paid via Stripe
- Add backfill-stripe-fees edge function to populate fee on existing paid invoices
- Migration: add stripe_fee column to invoices table
- Includes all pending portal changes (brand book, sign survey, task/project/company updates, etc.)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

supabase/functions/stripe-webhook/index.ts

@@ -0,0 +1,56 @@
+import { serve } from 'https://deno.land/std@0.168.0/http/server.ts';
+import { createClient } from 'https://esm.sh/@supabase/supabase-js@2';
+import Stripe from 'https://esm.sh/stripe@14?target=deno';
+
+const stripe = new Stripe(Deno.env.get('STRIPE_SECRET_KEY')!, { apiVersion: '2023-10-16' });
+const webhookSecret = Deno.env.get('STRIPE_WEBHOOK_SECRET')!;
+
+serve(async (req) => {
+  const body = await req.text();
+  const sig = req.headers.get('stripe-signature');
+
+  let event: Stripe.Event;
+  try {
+    event = await stripe.webhooks.constructEventAsync(body, sig!, webhookSecret);
+  } catch (err) {
+    console.error('Webhook signature failed:', err.message);
+    return new Response(`Webhook Error: ${err.message}`, { status: 400 });
+  }
+
+  if (event.type === 'checkout.session.completed') {
+    const session = event.data.object as Stripe.Checkout.Session;
+    const invoice_id = session.metadata?.invoice_id;
+
+    if (invoice_id) {
+      const supabase = createClient(
+        Deno.env.get('SUPABASE_URL')!,
+        Deno.env.get('SUPABASE_SERVICE_ROLE_KEY')!,
+      );
+
+      // Retrieve the Stripe processing fee from the balance transaction
+      let stripe_fee: number | null = null;
+      try {
+        const paymentIntentId = session.payment_intent as string;
+        if (paymentIntentId) {
+          const paymentIntent = await stripe.paymentIntents.retrieve(paymentIntentId, {
+            expand: ['latest_charge.balance_transaction'],
+          });
+          const charge = paymentIntent.latest_charge as Stripe.Charge | null;
+          const balanceTx = charge?.balance_transaction as Stripe.BalanceTransaction | null;
+          if (balanceTx?.fee != null) {
+            stripe_fee = balanceTx.fee / 100;
+          }
+        }
+      } catch (err) {
+        console.error('Failed to retrieve Stripe fee:', err.message);
+      }
+
+      const updateData: Record<string, unknown> = { status: 'paid' };
+      if (stripe_fee !== null) updateData.stripe_fee = stripe_fee;
+
+      await supabase.from('invoices').update(updateData).eq('id', invoice_id);
+    }
+  }
+
+  return new Response(JSON.stringify({ received: true }), { status: 200 });
+});