PR created by the Librarian CLI to initialize a release. Merging this PR
will auto trigger a release.

Librarian Version: v0.13.0
Language Image:
us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:234b9d1f2ddb057ed7ac6a38db0bf8163d839c65c6cf88ade52530cddebce59e
<details><summary>bigframes: v2.40.0</summary>

##
[v2.40.0](bigframes-v2.39.0...bigframes-v2.40.0)
(2026-05-13)

### Features

* Add `bigframes.execution_history` API to track BigQuery jobs (#16588)
([fa20a74](fa20a740))
  ```python
  import bigframes.pandas as bpd
  bpd.options.compute.enable_execution_history = True
  df = bpd.read_gbq("my_table")
  # ... perform operations ...
  history = bpd.execution_history
  print(history.jobs) # Access BigQuery job details for executed queries
  ```

* Implement `ai.similarity` and `ai.embed` for text embeddings and
semantic similarity (#16771, #16759)
([d4afa2c](d4afa2c8),
[fcb4579](fcb4579b))
  ```python
  import bigframes.pandas as bpd
  # Generate embeddings
  df["embeddings"] = bpd.bigquery.ai.embed(df["text_col"])
  # Compute similarity
df["similarity"] = bpd.bigquery.ai.similarity(df["embeddings_a"],
df["embeddings_b"])
  ```

* Support `hparam_range` and `hparam_candidates` parameters for
hyperparameter tuning in model creation (#16640)
([ca47835](ca47835c))
* Update `ai.score`, `ai.classify` and `ai.if_` parameters to match
their SQL equivalents (#16919, #16990, #16857)
([9f42fe1](9f42fe14),
[e9c52b1](e9c52b12),
[f3cb4ad](f3cb4ad0))
* Support unstable sorting in `sort_values` and `sort_index` (#16665)
([bbdeb70](bbdeb70f))
* Support loading Avro and ORC data formats (#16555)
([6d46cba](6d46cba3))
* Add NumPy ufunc support directly on column expressions (#16554)
([2f792ab](2f792abd))

### Bug Fixes

* Fix bugs compiling ambiguous ids and in subqueries (#16617)
([479e44d](479e44dd))

* BigFrames respects bq default region (#16933)
([ef9945a](ef9945a5))

* avoid views when querying BigLake tables from SQL cells (#16562)
([fdd3e0d](fdd3e0de))

* avoid `copy` argument warning in `to_pandas` (#16917)
([fe5245b](fe5245b8))

### Performance Improvements

* Improve write api upload throughput (#16641)
([ef856b0](ef856b04))

### Documentation

* Add docs to the to_csv methods of dataframe and series (#16570)
([a8fccef](a8fccefd))

</details>