Structured terminal-failure detail (kopia error class, stderr tail, retry
hint), written by the mover before it exits non-zero. ADR §4.10.
exitCode
integer
The process exit code, if one was reported.
kopiaErrorClass
string required
kopia error class (e.g. `RepositoryUnavailable`, `AuthFailure`).
message
string required
A short human-readable message: what failed, why, and how to fix it.
retryRecommended
boolean required
Whether retrying the same operation unchanged could succeed.
stderrTail
string
The last lines of kopia's stderr, if any were captured (bounded by
[`MAX_LOG_TAIL_BYTES`]).