Local entropy search as community contribution (#3302)

Summary:
## Motivation

This PR adds a BoTorch community implementation of Local Entropy Search (LES) [1], an information-theoretic local Bayesian optimization method.

LES targets information gain about the local descent sequence started from a current incumbent, rather than information gain about a global optimizer. In our paper we show that this is useful for high-complexity problems.

This PR adds a BoTorch re-implementation of our methods. The original code is available [here](https://github.com/Data-Science-in-Mechanical-Engineering/local-entropy-search).

This PR also adds a community notebook demonstrating LES on a Branin example.

### Have you read the [Contributing Guidelines on pull requests](https://github.com/meta-pytorch/botorch/blob/main/CONTRIBUTING.md#pull-requests)?

Yes.

Pull Request resolved: #3302

Test Plan:
Tests are in ``test_local_entropy_search.py``. Please let me know if additional tests are required.

## Related PRs

This PR is self contained and does not change existing functionality.

## References

[1] David Stenger, Armin Lindicke, Alexander von Rohr, Sebastian Trimpe.
*Local Entropy Search over Descent Sequences for Bayesian Optimization*. ICLR 2026.
[https://openreview.net/forum?id=cPxmLZmFa7](https://openreview.net/forum?id=cPxmLZmFa7)

Reviewed By: esantorella

Differential Revision: D103866761

Pulled By: Balandat

fbshipit-source-id: e79167dc89db0ce9da65459fe3f9f2c95f6bd0d9

Author: avrohr

botorch_community/acquisition/__init__.py

@@ -15,13 +15,15 @@
 from botorch_community.acquisition.input_constructors import (  # noqa F401
     acqf_input_constructor,
 )
+from botorch_community.acquisition.local_entropy_search import LocalEntropySearch
 from botorch_community.acquisition.rei import (
     LogRegionalExpectedImprovement,
     qLogRegionalExpectedImprovement,
 )
 from botorch_community.acquisition.scorebo import qSelfCorrectingBayesianOptimization
 
 __all__ = [
+    "LocalEntropySearch",
     "LogRegionalExpectedImprovement",
     "qBayesianQueryByComittee",
     "qBayesianVarianceReduction",