[Bug] Calendar sidebar schedules do not update live after rename/add/delete until page refresh

[DereC4]

Renaming, adding, or deleting schedules updates some local UI immediately, but the Calendar sidebar list stays stale until a full refresh.

Branch context: PR #838 introduced header rename UI and surfaced the issue

Steps To Reproduce

Open Calendar page.
Add a new schedule from sidebar.
Observe sidebar list does not reflect correctly until refresh.
Rename current schedule via header double-click.
Observe header title updates, but sidebar name remains stale until refresh.
Delete a schedule.
Observe sidebar list does not fully sync until refresh.
Expected
Sidebar schedule list updates in real time for add, rename, delete.

Actual

Sidebar list lags and only reflects changes after full page reload.

[linear]

UTRP-185

[DereC4]

The bug happened because in-place mutation kept the same array reference, so subscribers could skip rerender

[DereC4]

https://www.answeroverflow.com/m/1492475238389252106

[DereC4]

Oops, wrong link. Corrected: https://www.answeroverflow.com/m/1490536447223005345