Refactor get_NSSS_and_parameters to accept components instead of model struct

[Copilot]

Refactors get_NSSS_and_parameters and related functions to accept individual components (functions, workspaces, constants, equations) rather than the monolithic model struct, enabling more flexible usage patterns.

Changes

• get_NSSS_and_parameters: New primary signature accepts components directly with optional model parameter for default solver fallback
• get_custom_steady_state_buffer!: Now accepts workspaces struct directly
• evaluate_custom_steady_state_function: Accepts NSSS_custom function and workspaces separately
• AD rules: Updated rrule and ForwardDiff versions with optional caches_for_pullback/caches_for_derivatives parameters
• Convenience methods: Model-based signatures call through to component-based implementations

Usage

# Component-based (new)
SS_and_pars, (err, iters) = get_NSSS_and_parameters(
    model.functions, model.workspaces, model.constants, model.equations, 
    parameter_values; model = model
)

# Model-based (convenience wrapper)
SS_and_pars, (err, iters) = get_NSSS_and_parameters(model, parameter_values)

Note: The model keyword argument is required when using the default NSSS_solve (which is a generated function that needs the full struct). Models with custom steady state functions can omit it.

Original prompt

have get_NSSS_and_parameters accept functions, workspaces, and cahces instead of the main model struct. see whihc elements are necessary and replace th emain model struct as an input argument

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