Implement Undo toast flow for event deletion (day view) #1220

Priority

None

Feature Description

Add Undo toast capability when deleting an event from the agenda component in the day view. Reference the MVP POC in this commit: 5273cbf. Integrate an undo mechanism to allow users to quickly recover deleted events similar to other parts of the app.

Use Case

Users need a way to easily reverse accidental deletions of events from the agenda component in the day view. This improves user safety and confidence in managing their schedule.

• Delete shortcut deletes event when focused
• Undo deleting via toast click or shortcut
  • Use ctrl + z for windows users to undo | feat(web-planner): update task list #1129 (comment)
• Refetch after deleting / optimistically delete

Additional Context

Marked out-of-scope for the MVP because of complexity. POC exists in the above commit for future reference.

• Supporting the Undo toast flow when deleting an event from the agenda component on the day view. This turned out to be overly complex for this MVP. When returning to it, see this commit for a POC of the code you'd need.