fix: raise on append=True for unknown artifact_id (#1038)#1077

ishymko merged 3 commits into

a2aproject:maina2aproject/a2a-python:mainfrom

Linux2010:fix/artifact-append-unknown-id-error-1038Linux2010/a2a-python:fix/artifact-append-unknown-id-error-1038Copy head branch name to clipboard