Add Tax Exemption Certificate Upload
Add tax exemption handling to the Billing App, allowing customers to upload exemption certificates.
- Add "Tax Exempt" checkbox to customer billing settings
- Checkbox requires document upload when enabled
- Accept common document formats (PDF, images)
- Store uploaded certificates indefinitely (retention policy TBD with future offboarding requirements)
- No expiration date tracking for certificates
- Customer self-service is primary flow; PCI admins can also upload on behalf of customers
- Exemption takes effect immediately upon upload (no approval workflow)
- PCI staff reviews submissions after the fact and contacts customer directly if issues arise