[discussion] Add Timeline component (Scheduler)?

*⚠️ Info: This issue is for product research, to gather community input. In this [base-ui repo](https://github.com/mui/base-ui) we are, currently, focused on the core set of components needed to create a great design system, so the probability we build this in this repo is very low.*

## Summary

A component to organize time resources.

https://base-test.fibery.io/Allocation_Management/Allocations-by-project-29

This is at the intersection between (Big calendar) and #4781 (Gantt Charts). It relies on the control of Big Calendar to manipulate the time horizon, and it relies on the virtualization/grid support of #4781. But it's neither of those two.

## Examples in other libraries

- https://github.com/fullcalendar/fullcalendar
- https://bryntum.com/
- https://github.com/namespace-ee/react-calendar-timeline

*([internal benchmark](https://www.notion.so/mui-org/x-Timeline-component-Scheduler-2c1cbfe7b66080de87d9e902ab177d6e))*

### Motivation

- User requests:
- https://www.notion.so/mui-org/mui-x-Timeline-MRD-358cbfe7b66080aab24ffcfb7f14010b
- UI library requests:
- https://github.com/shadcn-ui/ui/issues/7371
- The equivalent request in MUI X: https://github.com/mui/mui-x/issues/20595. Now, it's not clear if this is something that we can deliver with a pure Base UI API, as it might be too low-level vs. the customization needs people have, but at the same time, the issue in MUI X is too positioned around Material UI, which is too opinionated. So opening this issue to have space for the community to contribute.