graceful ctrl c interrupt handling

[AnthonyPFAVG]

Description (e.g. "Related to ...", etc.)

This PR adds graceful SIGINT (Ctrl+C) handling to update_repository. Updates can be interrupted safely without leaving repositories in a half-way/undefined state. Previously, a KeyboardInterrupt raised during update execution could cause undefined behavior. Now, the update_respository() function catches the interrupt, logs it, and raises an UpdateFailedError.

A new unit test, test_update_repository_interrupts_gracefully, simulates a (Ctrl+C) interrupt to verify this behavior.

Code review checklist (for code reviewer to complete)

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR)
• Title summarizes what is changing
• Commit messages are meaningful (see this for details)
• Tests have been included and/or updated, as appropriate
• Docstrings have been included and/or updated, as appropriate
• Changelog has been updated, as needed (see CHANGELOG.md)

[n-dusan]

Thanks for the contribution!

Before we can review this PR, we need to clarify a licensing point. To meet the needs of our government partners, we’re considering moving to a dual-license model (AGPL-3.0 / Apache-2.0) in the future.

Because of that, we need confirmation that your contribution can be relicensed under Apache 2.0 as part of this dual-license setup if/when it happens.

If that works for you, let us know and we'll proceed with review and merging. If not, that's totally fine, we'll close the PR.

Thanks for understanding.