[core] Migrate away from deprecated Material UI APIs

[siriwatknp]

Context

Material UI v9 (skipping v8 to align with MUI X) will remove deprecated APIs. MUI X v9 must work with both MUI v7 and v9.

All new slots/slotProps APIs have been verified to exist in MUI v7, so migrating is safe for dual-version compatibility.

For cases where MUI v9 changes the shape of callback params (e.g. Autocomplete renderInput), MUI X can use the existing version-branching pattern: import { major as materialMajor } from '@mui/material/version' (see PickerFieldUI.tsx).

Phases

Phase	Scope	Complexity	Risk	Effort
1	Docs demos	Low	Low	~2h
2	Data Grid material adapter + grid generator	Medium	Medium	~4h
3	Scheduler Dialog slot migration	Low	Low	~1h
4	Pickers: Dialog/Snackbar slots + PickersTextField public API	High	High	~1-2 days

Popper TransitionProps — No action needed

Popper's TransitionProps in the render callback is NOT deprecated. Only Popper's root-level components/componentsProps are deprecated, and MUI X doesn't use those.

Already clean (not found in codebase)

• Deprecated composed CSS classes
• System props on Box/Typography/Stack
• BackdropComponent/BackdropProps, PopperComponent/PopperProps on Tooltip
• titleTypographyProps/subheaderTypographyProps on CardHeader
• imgProps on Avatar
• Theme variants placement

[linear]

X-4643

[github-actions]

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