[BUG] Deduplication Logic Not Tested Across Different Reminder Windows

[durdana3105]

Description
The deduplication test validates duplicate prevention only for identical timestamps. It does not verify behavior when reminder windows change.

Expected Behavior

Users should receive reminders once per valid reminder window.
New reminder windows should allow fresh task scheduling.

Proposed Solution

Add tests covering multiple reminder windows.
Verify deduplication expiration behavior.
Confirm tasks can be requeued after the intended cooldown period.

Assign this issue to me.

[durdana3105]

please assign it to me @vanshaggarwal27

[Birundalakshmi]

/claim