Add a seventh stalled-IPC case whose peer task shields outer
cancellation while subactor control IPC remains usable. Require
shield entry before SIGINT and child-side pending-cancel evidence
afterward, then prove cancel-ack budget expiry, runtime hard-reap,
SIGKILL status and completed OS reaping before watchdog rescue.
Keep the six existing cases and include the reviewed provenance
pair with corrected human attribution. This models a shielded Trio
task, not an uninterruptible kernel call.
Prompt-IO: ai/prompt-io/opencode/20260929T222213Z_68e9c49f_shielded_peer.md
(this patch was generated in some part by `opencode` using
`gpt-6.1-sol` (`openai`))