Fix scheduler task detail modal close flow

[ruizanthony]

Summary

• Track when the scheduler parent modal is open before showing task detail.
• Close the task detail modal explicitly and close the scheduler modal when required.
• Preserve the edit flow by reopening/focusing the scheduler modal after closing detail.

Checks

• node --check webui/components/modals/scheduler/scheduler-store.js
• git diff --check --cached before commit

Only webui/components/modals/scheduler/scheduler-store.js is included in this commit.