AJDA-2169 - Switch autosave to data-loader internal endpoint

[ErikZigo]

Release Notes

• Prepares notebook autosave to work without a Storage API token, as part of the broader effort to remove tokens from Jupyter sandbox containers
• Switches the autosave script to use the data-loader's internal save path, restricted to localhost only
• This release has no user-facing effect on its own — it only takes effect once new JupyterLab images are built with this package and distributed via runtimes
• Aligns minimum Python version (3.10) with what's actually running in Keboola Jupyter container images

Change Type

Minor

Impact Analysis

• Who's affected: Jupyter-type sandbox users and the autosave background process
• Main value: Removes the need to expose a Storage API token inside notebook containers
• Risks: Low — requires data-loader 4.3 (deployed via sandboxes#575) to already be in place; the internal save endpoint must be available before new JupyterLab images are distributed

Customer Communication Plans

No external communication needed. The user experience is identical — notebooks continue to autosave transparently.

Justification

Jupyter sandbox containers currently require a Storage API token for notebook autosave, which is a security concern. This change is step 2 of a multi-phase effort to remove storage tokens from sandbox containers entirely, as part of the Sandbox API deprecation initiative.

Deployment Plan

• Merge and release notebook-utils 2.3.0
• Build new JupyterLab sandbox images for Python 3.10 containing the updated notebook-utils
• Register the new images in Sandboxes runtimes

Rollback Plan

Since this release has no effect on its own, no rollback is needed at this stage. If issues arise after step 3 (new JupyterLab images), rebuild the images with the previous notebook-utils version 2.2.0 to restore the original token-based autosave path. No data loss or service disruption expected.

Post-Release Support Plan

• Watch for unexpected errors on the internal save path
• Confirm autosave continues to work correctly across all sandbox environments

[linear]

AJDA-2169 [data-loader-api] new endpoint for Files autosave