[Snyk] Security upgrade python from 3.9 to 3.14.3

[trongthanht3]

Snyk has created this PR to fix 2 vulnerabilities in the dockerfile dependencies of this project.

Keeping your Docker base image up-to-date means you’ll benefit from security fixes in the latest version of your chosen image.

Snyk changed the following file(s):

• docker/backend.dockerfile

We recommend upgrading to python:3.14.3, as this image has only 221 known vulnerabilities. To do this, merge this pull request, then verify your application still works as expected.

Vulnerabilities that will be fixed with an upgrade:

	Issue	Score
	Heap-based Buffer Overflow SNYK-DEBIAN13-IMAGEMAGICK-15044354	714
	Heap-based Buffer Overflow SNYK-DEBIAN13-IMAGEMAGICK-15044354	714
	Heap-based Buffer Overflow SNYK-DEBIAN13-IMAGEMAGICK-15044354	714
	Release of Invalid Pointer or Reference SNYK-DEBIAN13-IMAGEMAGICK-15044366	714
	Release of Invalid Pointer or Reference SNYK-DEBIAN13-IMAGEMAGICK-15044366	714

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Important

• Check the changes in this PR to ensure they won't cause issues with your project.
• Max score is 1000. Note that the real score may have changed since the PR was raised.
• This PR was automatically created by Snyk using the credentials of a real user.

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🦉 Heap-based Buffer Overflow

[Copilot]

Pull request overview

This PR updates the backend Docker image base to a newer Python version to reduce vulnerabilities flagged by Snyk.

Changes:

• Bump docker/backend.dockerfile base image from python:3.9 to python:3.14.3.

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[Copilot]

backend.dockerfile is being bumped to Python 3.14.3 while docker/celeryworker.dockerfile still builds from Python 3.10 and both images install the same Poetry project from /src. This increases the risk of runtime differences (dependency wheels/ABI, behavior changes) between backend and worker. Consider aligning both Dockerfiles to the same Python minor/patch level (or document why they intentionally differ) to avoid hard-to-debug inconsistencies.