Automatic model search

Toolset forecast_tuning: 1 tool.

Tool	What it does	Notes
`forecast_auto_ml`	Searches, for each chosen model, its hyperparameters together with the features (candidate lags, EWM and rolling means, calendar features and target transforms such as log, differencing and scaling, shaped by the season) to minimize the backtest error over n_windows windows, then retrains the best configuration on all data and forecasts h periods with conformal bands.

Inputs, limits and outputs are described in Fincept Forecast. Full schemas: fincept_describe_tool.