Is your feature request related to a problem? Please describe.
Currently, sharedKoinViewModel requires accessing NavBackStackEntry.destination.parent?.route internally, which limits flexibility when handling nested navigation graphs or dynamic parent graph routes.
In some cases, we need to explicitly specify a navGraphRoute different from destination.parent?.route for advanced navigation setups (e.g., shared ViewModel across sibling graphs).

Describe the solution you’d like
Introduce an overload of sharedKoinViewModel with an optional navGraphRoute parameter:

@Composable
inline fun <reified VM : ViewModel> NavBackStackEntry.sharedKoinViewModel(
    navController: NavController,
    navGraphRoute: Any? = this.destination.parent?.route,
): VM {
    val navGraphRoute = navGraphRoute ?: return koinViewModel<VM>()
    val parentEntry = remember(this) {
        navController.getBackStackEntry(navGraphRoute)
    }
    return koinViewModel(
        viewModelStoreOwner = parentEntry
    )
}

This allows developers to explicitly pass the navGraphRoute or fall back to the current default logic.

Describe alternatives you’ve considered
• Creating a custom extension in each project (current workaround, but not ideal for reusability).
• Using a wrapper function to pass route manually (less clean than built-in support).

Target Koin project
• koin-compose-viewmodel-navigation