Return tool-call images instead of dropping them - #1963

Actions cache usage is 10.60 GB of 10.00 GB (106%) across 35 entries. GitHub evicts least-recently-used entries without reporting it, so caches are about to start missing. Run `gh cache list --limit 100 --json key,sizeInBytes` to find the job writing oversized entries; a job on a Blacksmith Linux runner should not appear here at all.