- Added `last_reminder_mail_sent_at` field to track reminder
timestamps.
- Implemented `can_send_reminder` to check if a reminder can be
sent based on a 30-minute cooldown.
- Added `reminder_cooldown_remaining` to get remaining cooldown
time.
- Added `mark_reminder_sent` to update reminder timestamp.
- Added example demonstrating reminder functionality in
`legal_contract_example.rs`.
- Added tests for reminder functionality in
`test_reminder_functionality.rs`.
- Updated Rhai scripts to include reminder-related functions and
tests.
- Improved formatting and clarity in example code.
