fingerPro 2.0

This pull request updates the fingerPro package to version 2.0, incorporating a major refactoring and a shift in focus toward more robust data validation and a streamlined workflow. The changes are a consolidation of developments since version 1.3, including:

Key Changes:

• API Standardization and Refinements: The function naming convention has been normalized to snake_case for consistency. Several function signatures, such as CB_method and unmix, have been simplified and arguments have been reordered, which may introduce breaking changes.

• Enhanced Data Handling and Utilities: A new central module (R/functions.R) was created to handle common utilities and data validation. This module exposes functions like check_database, select_tracers, and raw_dataset, which were previously internal, to empower users with better dataset preparation and integrity checks.

• Extended Functionality: The package now includes new capabilities in the unmixing engine, such as Linear Variability Propagation (LVP) and unconstrained variants. New analysis functions like individual_tracer_analysis.R have also been added.

• Updated Metadata and Dependencies: The package title, authorship, and maintainer information have been updated. Dependencies, including plotly and tibble, have been added or refined to support new visualization and data handling features.

• Documentation: The documentation has been revised and consolidated to focus on the stable API.