Maintenance Release - Various Improvements across models, acquisition function optimization, PFN integration

Compatibility

• Require GPyTorch>=1.14.2 (#3055).

New Features

• Add EnsembleMapSaasSingleTaskGP (#3035, #3038, #3040).
• Allow different inferred noise levels for each task in MultitaskGP (#2997).
• Allow LatentKroneckerGP model to support different T values at train and test time (#3032, #3037).
• Allow qHypervolumeKnowledgeGradient to return log values for better numerical stability (#2974, #2976, #2979).
• Add NumericToCategoricalEncoding input transform (#2907).
• Added a MatheronPathModel - a DeterministicModel returning a Matheron path sample (#2984).
• Project points generated in acquisition function optization to the feasible space (#3010).
• Add support for non-uniform model weights in EnsembleModel and EnsemblePosterior (#2993).
• Allow optimizers to support negative indices for fixed features (#2970).
• Add worst known feasible value to constrained test problems (#3016).

Bug Fixes

• Fix optimize_acqf_mixed_alternating initialization with categorical features (#2986).
• Use IIDNormalSampler for PosteriorList by default to fix issue with correlated Sobol samples (#2977).
• Fix condition_on_observations to correctly apply input transforms and properly add data to train_inputs (#2989, #2990, #3034).
• Fix handling of input transforms for AdditiveMapSaasSingleTaskGP (#3042).
• Preserve train inputs and targets through transforms (#3044).
• Improve how qNEHVI handles pending points to avoid duplicate suggestions when initial pending points are passed (#2985).

Other Changes

• Add support for missing tasks in multi-task GP models (#2960).
• Add input constructor for LogConstrainedExpectedImprovement (#2973).
• Improve error handling and update documentation for inter-point constraints (#3003).
• Make AnalyticAcquisitionFunction._mean_and_sigma() return output dim consistently (#3028).
• Improve initialization with continuous relaxation in optimize_acqf_mixed_alternating (#3041).
• Implement ContextualDataset.__eq__() (#3005).
• Check shape of state dict when comparing input transforms (#3051).
• Add py.typed file to precent tools complainnig about type stubs (#2982).
• Improve best feasible objective computation; point user to use probability of feasibility (#3011).

Deprecations and removals

• Deprecate get_fitted_map_saas_ensemble() in favor of EnsembleMapSaasSingleTaskGP (#3036).

Changes to botorch_community

• Add MCAcquisition support to PFNModel (#3031).
• Add copula-based multivariate posterior for PFNModel (#3045).
• Allow PFNModel to load checkpoints from trainings done with automl/PFNs (#3017).
• Add support for Kaiming/He initialization for the VBLL mean (#3053).