Redo the gantt chart

[bbovenzi]

Replace the chartjs gantt chart with a custom implementation that is fully integrated with our grid view. Such as:

• Virtualized gantt chart & synced scrolling
• Same colors and iconography
• No animations between changing views

Closes: #63727
Closes: #56070

Also, added a new Gantt button next to the grid and graph buttons to make it easier to find.

Leaving this as a draft until #63372 is merged so that we can incorporate queued and scheduled times too

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Was generative AI tooling used to co-author this PR?

• Yes Claude Sonnet 4.6

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