Under the hood
Staged file-list credential handling now blocks reuse and cancellation of the fetch
What
The internal worker code that fetches the list of staged files and parses the credentials for it was hardened. The fetch can now be cancelled with an AbortSignal (a standard way to stop an in-progress operation), and the credential-parsing step is wrapped by a single-use guard: if it is somehow triggered a second time, it fails immediately with the error read failed: credential expired instead of proceeding.
Why
This closes off a case where stale or reused credentials could be parsed twice, which could otherwise lead to confusing failures or wasted work. It also lets this internal fetch be cancelled cleanly if it's no longer needed.