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>

index.html

@@ -9,6 +9,8 @@
         document.documentElement.style.colorScheme = theme === 'light' ? 'light' : 'dark';
       })();
     </script>
+    <link rel="preconnect" href="https://fqflxxqvennhvoeywrdw.supabase.co" crossorigin />
+    <link rel="dns-prefetch" href="https://fqflxxqvennhvoeywrdw.supabase.co" />
     <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
     <link rel="icon" type="image/png" sizes="32x32" href="/favicon-32.png" />
     <link rel="icon" type="image/png" sizes="16x16" href="/favicon-16.png" />