Fixes b/464971054 🦕

This PR adds support for `CREATE MODEL` statement in BigQuery ML via
`bigframes.bigquery.ml.create_model`.
It includes DDL generation logic handling various clauses like
TRANSFORM, OPTIONS, remote models, and different data input formats.
It also refactors `bigframes.core.sql` into a package to support the new
submodule.


---
*PR created automatically by Jules for task
[3846335972146851433](https://jules.google.com/task/3846335972146851433)
started by @tswast*

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>
Co-authored-by: Tim Sweña <swast@google.com>

This PR addresses a flaky ZMQError: Address already in use that
occasionally occurred during parallel notebook test execution.

  **Problem:**
The bigframes.display module eagerly imported anywidget and traitlets at
module load time (`bigframes/display/__init__.py`). This meant that when
multiple Jupyter kernels were spun up simultaneously by nox for parallel
testing, they would all try to initialize traitlets.HasTraits objects
with sync=True properties. This led to race conditions and ZMQ port
conflicts, causing notebook tests (including those that did not directly
use anywidget like `streaming_dataframe.ipynb`) to fail. Log is
[here](https://fusion2.corp.google.com/invocations/72088900-0196-4441-944b-ad68e491a8f8/targets/bigframes%2Fpresubmit%2Fnotebook/log).

  **Solution:**
The TableWidget class import in `bigframes/display/__init__.py` has been
refactored to use Python's `__getattr__` for lazy loading. This ensures
that anywidget and traitlets are only imported and their associated
kernel communication channels are initialized when display.TableWidget
is actually accessed by the code. This prevents premature initialization
and eliminates the port collision race condition during parallel test
startup.

Fixes #<465768150> 🦕

Thank you for opening a Pull Request! Before submitting your PR, there
are a few things you can do to make sure it goes smoothly:
- [ ] Make sure to open an issue as a
[bug/issue](https://github.com/googleapis/python-bigquery-dataframes/issues/new/choose)
before writing your code! That way we can discuss the change, evaluate
designs, and agree on the general idea
- [ ] Ensure the tests and linter pass
- [ ] Code coverage does not decrease (if any source code was changed)
- [ ] Appropriate docs were updated (if necessary)

Fixes b/447388852 🦕

…arning (#2314)

Moved `ignore::pandas.errors.SettingWithCopyWarning` from `pytest.ini`
to `conftest.py` with a check for its existence. This fixes
`AttributeError: module 'pandas.errors' has no attribute
'SettingWithCopyWarning'` when running tests against pandas 3.0.

---
*PR created automatically by Jules for task
[1336882389279070030](https://jules.google.com/task/1336882389279070030)
started by @tswast*

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

🦕

… to avoid time travel (#2318)

See internal issue b/310266666 🦕

revert "refactor: Migrate DataFrame display to use IPython's
_repr_mimebundle_() protocol for anywidget mode (#2271)"

This reverts commit 41630b5 for bug
466155761.
Verified at Colab: screen/AjTEQC8SrSfMqhN

Fixes #< 466155761 > 🦕

Moved long-running ML tests to the large directory to improve test suite
organization and execution time management. This involves creating new
test files in `tests/system/large/ml/` and appending to existing ones,
while removing the corresponding tests from `tests/system/small/ml/`.

---
*PR created automatically by Jules for task
[11110816135219701367](https://jules.google.com/task/11110816135219701367)
started by @tswast*

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

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

Librarian Version: v0.7.0
Language Image:
us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:c8612d3fffb3f6a32353b2d1abd16b61e87811866f7ec9d65b59b02eb452a620
<details><summary>bigframes: 2.31.0</summary>

##
[2.31.0](v2.30.0...v2.31.0)
(2025-12-10)

### Features

* add `bigframes.bigquery.ml` methods (#2300)
([719b278](719b278c))

* add &#39;weekday&#39; property to DatatimeMethod (#2304)
([fafd7c7](fafd7c73))

### Bug Fixes

* cache DataFrames to temp tables in bigframes.bigquery.ml methods to
avoid time travel (#2318)
([d993831](d9938319))

### Reverts

* DataFrame display uses IPython&#39;s `_repr_mimebundle_` (#2316)
([e4e3ec8](e4e3ec85))

</details>