This PR is _almost_ able to close issue #89127.
Sadly, no `InheritedModel` or custom `RenderObject`s today; instead the [WidgetState operators](https://main-api.flutter.dev/flutter/widgets/WidgetStateOperators.html) have been restructured to support equality checks.
`WidgetStateProperty.fromMap()` is now capable of accurate equality checks, and all of the `.styleFrom()` methods have been refactored to use that constructor.
(Equality checks are still broken for `WidgetStateProperty.resolveWith()`, and any other non-`const` objects that implement the interface.)
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credit for this idea goes to @justinmc: https://github.com/flutter/flutter/issues/89127#issuecomment-2313187703
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