- Members paying via installments (down_payment) now enter 'pending_cheques'
  status instead of being immediately activated
- Membership number is only assigned after ALL cheques are uploaded
  (1 cheque per installment month)
- Dependents (spouses/children) are NOT auto-included in installment
  payments — they must pay addition_fee separately
- New installment_cheques table stores serial, bank, date, scan file
- New ChequeController + ChequeService for upload flow
- Employee uploads cheque scans from installment plan page
- Member show page displays pending_cheques banner with upload link
- Auto-activates member once all required cheques are submitted
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>