[Bug]: When updating a task using browser mode, the update time does not match the local time

[yinzhenyu-su]

Describe the bug
When updating a task using browser mode, the update time does not match the local time，my timezone is UTC+8

To Reproduce
Steps to reproduce the behavior:

1. Create and update tasks in the browser.
2. Check update time and local time.

Expected behavior
The update time is the same as the local time.
Environment

• OS: [MacOS 15.7]
• Node version: [22]

Additional context
Perhaps the dayjs library can be introduced to solve this problem.

Backlog.md/src/core/backlog.ts

Line 307 in fd5c708

task.updatedDate = new Date().toISOString().slice(0, 16).replace("T", " ");

[dkmin]

+1
not only browser mode but *.md file

created_date: '2025-10-07 00:20'
updated_date: '2025-10-07 02:30'