Have isRetryableError also inspect the returned error, not just the
captured output. Streamed commands (amend, commit, and other operations
run through the gpg helper) don't capture output, so their index.lock
failures were slipping past the retry loop and surfacing to the user as
a hard "Git command failed". Now they retry like every other command.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
c1cd500fa7