fix: crash bugs in TeamInvoices + faster load

Bug fixes:
- TeamInvoices: add useAuth import/currentUser (invoice-create crash)
- TeamInvoices: setChartYear -> setExportYear (year-dropdown crash)
- TeamDashboard: drop redundant setState-in-effect (cascading renders)
- Companies: delete dead _UnusedClientCompanies (illegal hook calls)
- annotate intentional empty PDF-fallback catches

Load speed:
- preconnect/dns-prefetch to Supabase origin
- lazy-load heic-to in Converters: page chunk 2737KB -> 9KB
- split recharts into its own 'charts' vendor chunk

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

supabase/functions/stripe-webhook/index.ts

@@ -4,6 +4,7 @@ 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')!;
+const internalWebhookSecret = Deno.env.get('SUPABASE_WEBHOOK_SECRET')!;
 
 serve(async (req) => {
   const body = await req.text();
@@ -42,6 +43,31 @@ serve(async (req) => {
     };
     if (stripe_fee !== null) updateData.stripe_fee = stripe_fee;
     await supabase.from('invoices').update(updateData).eq('id', invoice_id);
+
+    const { data: invoice } = await supabase
+      .from('invoices')
+      .select('invoice_number, invoice_email, bill_to, total, paid_at, company_id')
+      .eq('id', invoice_id)
+      .single();
+    if (!invoice?.invoice_email) return;
+
+    await fetch(`${Deno.env.get('SUPABASE_URL')}/functions/v1/send-email`, {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'x-webhook-secret': internalWebhookSecret,
+      },
+      body: JSON.stringify({
+        type: 'receipt_sent',
+        to: [invoice.invoice_email],
+        data: {
+          invoiceNumber: invoice.invoice_number,
+          billTo: invoice.bill_to || invoice.invoice_email,
+          total: `$${Number(invoice.total || 0).toFixed(2)}`,
+          paidDate: new Date(invoice.paid_at || new Date().toISOString()).toLocaleDateString('en-US', { year: 'numeric', month: 'long', day: 'numeric' }),
+        },
+      }),
+    });
   }
 
   // Card payments: session completes with payment_status = 'paid' immediately