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

Librarian Version: v1.0.0
Language Image:
us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:b8058df4c45e9a6e07f6b4d65b458d0d059241dd34c814f151c8bf6b89211209
<details><summary>google-cloud-spanner: 3.63.0</summary>

##
[3.63.0](v3.62.0...v3.63.0)
(2026-02-13)

### Features

* add requestID info in error exceptions (#1415)
([2c5eb96](2c5eb96c))

### Bug Fixes

* prevent thread leak by ensuring singleton initialization (#1492)
([e792136](e792136a))

### Documentation

* snippet for setting read lock mode (#1473)
([7e79920](7e79920c))

</details>