Feature/gantt chart improvements

[JoshuaGoldberg]

Changes

Gantt Chart Improvements, WIP

Notes

Any other notes go here

Test Cases

• Case A
• Edge case
• ...

Screenshots

If you made UI changes you must post a screenshot of the whole page for each change in 1) a normal sized window and 2) the smallest possible window

If you did any manual testing (e.g., with Postman), put screenshots of the http request and before and after of the db

If none of this applies, you can delete this section

To Do

Any remaining things that need to get done

• item 1
• ...

Checklist

It can be helpful to check the Checks and Files changed tabs.
Please review the contributor guide and reach out to your Tech Lead if anything is unclear.
Please request reviewers and ping on slack only after you've gone through this whole checklist.

• All commits are tagged with the ticket number
• No linting errors / newline at end of file warnings
• All code follows repository-configured prettier formatting
• No merge conflicts
• All checks passing
• Screenshots of UI changes (see Screenshots section)
• Remove any non-applicable sections of this template
• Assign the PR to yourself
• No yarn.lock changes (unless dependencies have changed)
• Request reviewers & ping on Slack
• PR is linked to the ticket (fill in the closes line below)

Closes # (issue #)