Add Project Files section and show company name for external users on project detail

supabase/migrations/20260513190000_add_sub_invoice_number_fn.sql

@@ -0,0 +1,9 @@
+create or replace function public.get_next_sub_invoice_number()
+returns text
+language sql
+security definer
+set search_path = public
+as $$
+  select 'INVSUB-' || extract(year from now())::text || '-' || lpad((count(*) + 1)::text, 3, '0')
+  from public.subcontractor_invoices;
+$$;