Feature Request: Option to Delay Receiver Notification & Tracking Until Delivery Date

Currently, when scheduling a pickup for a courier, the receiver gets notified immediately. While this is useful for regular shipments, it creates an issue when sending gifts, as it ruins the surprise.

there are many use cases where prior notification is not needed.

Proposed Solution
Provide an option to delay the notification to the receiver until the date of delivery or allow senders to choose when the notification should be sent.

**Expected Behavior**
When scheduling a pickup, the sender should have an option like:
"Notify receiver immediately" (default)
"Notify receiver on delivery date"

If the sender selects the delayed notification option, the receiver will only be notified once the package is out for delivery or delivered.

Context
This small feature would improve the user experience for gift senders while keeping the notification system functional for regular shipments.

Start by locating the pickup-scheduling and receiver-notification entry points, then trace how the delivery date and sender preferences are represented. Define how the delayed option affects notifications through delivery or out-for-delivery, while preserving immediate notification as the default; done means both choices work reliably.

Written by the indexing model from the issue text.