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

supabase/migrations/20260513220000_sub_delete_submitted_invoices.sql

@@ -0,0 +1,5 @@
+-- Allow subs to delete their own draft or submitted invoices (not paid)
+drop policy if exists "Sub delete own draft invoices" on public.subcontractor_invoices;
+
+create policy "Sub delete own unpaid invoices" on public.subcontractor_invoices
+  for delete using (profile_id = auth.uid() and get_my_role() = 'external' and status != 'paid');