Support for {lcmm}

[strengejacke]

Fixes #1169

[strengejacke]

@gemini-code-assist review

[Copilot]

Pull Request Overview

This pull request adds support for the {lcmm} package, which provides tools for latent class mixed models. The PR implements parameter extraction, p-value calculation, and standard error methods for lcmm model objects.

• Adds comprehensive support for lcmm, externVar, and externX model classes
• Updates documentation and examples to remove dependencies on factoextra package
• Includes extensive test coverage with snapshot testing for various model types

Reviewed Changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
R/methods_lcmm.R	Implements core methods for extracting parameters, p-values, and standard errors from lcmm models
tests/testthat/test-lcmm.R	Comprehensive test suite with snapshot testing for different lcmm model configurations
tests/testthat/_snaps/lcmm.md	Snapshot test expectations for lcmm model outputs
R/extract_parameters.R	Updates generic parameter extraction to support Group column merging for lcmm models
R/ci_generic.R	Adds Group column support for confidence interval calculations
NAMESPACE	Exports new S3 methods for lcmm model classes
DESCRIPTION	Adds lcmm as suggested dependency
Various documentation files	Updates examples to use conditional checks instead of requiring factoextra

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[gemini-code-assist]

Code Review

This pull request adds support for lcmm models, which is a great addition. The changes include new methods for model_parameters, p_value, and standard_error, along with necessary updates to generic functions, documentation, and tests. The code is well-structured, and the formatting improvements in other files enhance readability. I have one suggestion to refactor the new lcmm methods to reduce code duplication, which will improve long-term maintainability.