fix(docker): sync python 3.14-slim digest for PR 1389

[seonghobae]

Description

Follow-up for Dependabot #1389. Dependabot bumped only the root Dockerfile FROM digest for python:3.14-slim to sha256:ce40764625a4ff50df3548277632e7f96c4e77fe75fa848aae9885476e7df5a4. That left ARG OCI_IMAGE_BASE_DIGEST / OCI_IMAGE_BASE_NAME and connector/Dockerfile on the previous digest, so Python 3.14 test_release_governance failed on pin drift.

This commit (2df62d87) is also pushed to dependabot/docker/docker-base-images-6dafb4a59b so #1389 can go green without a squash or empty requeue.

Syncs the same digest across:

• root Dockerfile FROM
• OCI base.digest / base.name default ARGs
• connector/Dockerfile FROM

Does not bump VERSION. Does not touch #1376 or #1392.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Verification

cd backend
PYTHONWARNINGS=error DISABLE_BACKGROUND_WORKERS=1 python -m pytest \
  tests/test_release_governance.py::test_container_images_cover_all_oci_predefined_image_annotations \
  tests/test_release_governance.py::test_container_base_image_pins_are_synchronized \
  tests/test_release_governance.py::test_python_314_backend_image_uses_binary_wheel_dependencies -q

Local Python 3.14.7 evidence: 3 passed.

PR 1389 OCI pin tests

  

[github-actions]

PR governance metadata gate is not ready for 2df62d87373f917d0dd1f6702c66d8c1a1b97c3b:

• Draft PR: merge automation is paused.
• Required check security is FAILURE on the current head.

[seonghobae]

중복 repair lane 정리: 현재 Dependabot #1389 head 2c76e907c130702dbd34978bb8ce118981377d73가 이 repair head 2df62d87373f917d0dd1f6702c66d8c1a1b97c3b를 직접 ancestor로 포함합니다. root/connector/OCI Python 3.14 base digest 동기화는 canonical Dependabot branch에 보존되었으므로 별도 repair PR은 superseded로 종료합니다. #1389의 current-head Checks와 리뷰는 별도로 검증해야 합니다.