feat(capa): allow overdue CAPAs to be acted on, fix owner page stats

- CapaOwnerActions: add 'overdue' to open/reopened branch so DB-overdue
  CAPAs show 'Mark In Progress' button (cron transitions open→overdue)
- capa-owner page: compute overdue at runtime (dueDate < today) so stats
  and red highlight are correct even before cron runs
- openCount now excludes overdue items to avoid double-counting
- Add CapaOwnerActions test suite covering all status transitions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HEYxFQiCyxJvnBCoZeYzB9

components/capa/capa-owner-actions.tsx

@@ -31,7 +31,7 @@ export function CapaOwnerActions({ capaId, currentStatus }: Props) {
     }
   }
 
-  if (currentStatus === 'open' || currentStatus === 'reopened') {
+  if (currentStatus === 'open' || currentStatus === 'reopened' || currentStatus === 'overdue') {
     return (
       <button
         onClick={() => updateStatus('in_progress')}