New protocol_test covers two previously-untested cross-process contracts:
- publish_pads/read_pads seqlock: a concurrent writer + reader run for ~700 ms;
the reader (2.5M snapshots) never observes a torn snapshot, and read_pads
returns false (bounded, no hang) when the sequence is stuck odd mid-write.
- IpcClient::connect refuses a section with a mismatched version or a bad magic,
and accepts a matching header -- the ABI safety net that only had happy-path
coverage before.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
