- Implemented the ability for admins to grant subscriptions to doctors and clinics without payment.
- Added new API endpoint `/api/v1/admin/subscription/grant` for granting subscriptions.
- Updated the subscription model to track the admin who granted the subscription.
- Enhanced the subscription report to include details about granted subscriptions.
- Introduced a new `is_granted` field to indicate if a subscription was granted by an admin.
- Updated the database schema to support the new functionality with a migration.
- Added tests to ensure the correct behavior of the subscription granting process.
