Allow users to receive a message multiple times (user-defined schedules)

[ibsule]

Summary

Allow users to specify times for receiving the same message more than once at creation time.

Details

• Update message creation UI to let user specify all desired delivery times
• Store all the scheduled times for each message
• Update backend delivery logic to handle multiple sends for the same message
• UI should clearly show when and how many times a message will be sent

Motivation

Empowers users to schedule important messages for repeated delivery as needed for reminders, motivation, or other use-cases.