Add MATLAB GRF_Representativeness project scaffold

[nikegoose]

Motivation

• Provide a ready-to-develop MATLAB project layout to evaluate representativeness of forecast days using KS-distance selection, empirical heuristics, and UTCI impact analysis.
• Give clear, modular entry points and small working stubs so downstream algorithm development and data integration can proceed quickly.
• Include minimal tests and .gitignore hygiene so local data (e.g. MyWRFdata.mat) can remain out of version control.

Description

• Added the GRF_Representativeness/ directory tree and a pipeline entrypoint main.m that wires configuration and runs run_stream1 → run_stream2 → run_stream3 and saves a final summary.
• Implemented configuration modules config_paths.m, config_parameters.m, and config_plot.m for paths, parameters, and plotting defaults.
• Added data_io/ stubs for load_wrf_field, load_station_data, load_preprocessed_mat, and save_intermediate, and core utilities including compute_ks_distance, compute_distribution, select_representative_days, generate_ensemble_perturbation, compute_utci (simplified proxy), and cross_validation_split.
• Implemented three stream scaffolds under stream1_forecast_based/, stream2_empirical_methods/, and stream3_utci_impact/ with orchestration and simple placeholder logic, figure helpers in figures/, result/intermediate folders, and basic unit/smoke tests in tests/.
• Added .gitignore entry to exclude MyWRFdata.mat and other common local artifacts.

Testing

• Verified file and folder layout with find GRF_Representativeness -maxdepth 3 -type d -o -type f | sort, which succeeded and listed the created files and directories.
• Attempted to run the MATLAB test suite with matlab -batch "runtests('GRF_Representativeness/tests')", which failed because MATLAB is not available in this environment (bash: command not found: matlab).
• Queried repository state with git status --short && git rev-parse --short HEAD to validate changes were staged and a working tree revision exists, which returned a short HEAD identifier.

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Codex Task