fix: improve error message when download directory cannot be created

[rickrams]

When downloading job output, if the target directory cannot be created (e.g. due to cross-OS path incompatibility like Linux paths on macOS where /home is a synthetic firmlink), the raw OSError was surfaced with a cryptic errno. This wraps the mkdir call with a clear error message that explains the failure and suggests re-running the download to choose a valid local path.

How was this change tested?

See DEVELOPMENT.md for information on running tests.

• Have you run the unit tests? Yes
• Have you run the integration tests? No
• Have you made changes to the download or asset_sync modules? No

Was this change documented?

• Are relevant docstrings in the code base updated? N/A
• Has the README.md been updated? N/A

Does this PR introduce new dependencies?

This library is designed to be integrated into third-party applications that have bespoke and customized deployment environments. Adding dependencies will increase the chance of library version conflicts and incompatabilities. Please evaluate the addition of new dependencies. See the Dependencies section of DEVELOPMENT.md for more details.

• This PR adds one or more new dependency Python packages. I acknowledge I have reviewed the considerations for adding dependencies in DEVELOPMENT.md.
• This PR does not add any new dependencies.

Is this a breaking change? No

A breaking change is one that modifies a public contract in a way that is not backwards compatible. See the
Public Contracts section
of the DEVELOPMENT.md for more information on the public contracts.

If so, then please describe the changes that users of this package must make to update their scripts, or Python applications.

Does this change impact security? No

• Does the change need to be threat modeled? For example, does it create or modify files/directories that must only be readable by the process owner?
  • If so, then please label this pull request with the "security" label. We'll work with you to analyze the threats.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud