conf(compose & chart): upgrade backend & bump chart

[thomasboni]

No description provided.

[cursor]

PR Summary

Low Risk
Version-only changes to chart metadata and default image tags; no application or template logic modified in this diff.

Overview
Bumps the Plumber Helm chart from 1.4.0 to 1.4.1 and pins the backend image from v2.41.0 to v2.41.1 for both backend and worker in chart values.

versions.env is updated so BACKEND_IMAGE_TAG matches v2.41.1; the frontend tag is unchanged.

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