bug: countup is off by 1

[jan-Sanku]

Prerequisites

• I have read the Contributing Guidelines.
• I agree to follow the Code of Conduct.
• I have searched for existing issues that already include this feature request, without success.

Countdate version

1.5.11

Current Behavior

when entering a countup of the current day, the count reads 0 (this is correct).
however, when entering a countup of yesterday, the count also reads 0!

in general, any date in the past is off by 1. as of writing this (2026-02-24) the app shows "23 days" for 2026-01-31, which was actually 24 days ago.

Expected Behavior

the countup should reliably answer the question "how many days ago was [date]?". today on 2026-02-24, the date 2026-01-31 should read "24 days", and selecting yesterday at any point should read "1 day".

Steps to Reproduce

• create a countup for any day in the past

Additional Information

No response