[cadence 4b0cbff0a79dc220] Rollback exchanges with the current stable entry without confirming it is still this attempt's link, then deletes the displaced entry. This can destroy a concurrent owner's  #240

Raised at crates/baley/src/update/deliver.rs:292 as high by openai, ruled downgraded.

Claim. Rollback exchanges with the current stable entry without confirming it is still this attempt's link, then deletes the displaced entry. This can destroy a concurrent owner's replacement.

Failure scenario. An owner replaces the observed link with X just before the updater's exchange. The updater exchanges in its candidate, discovers X in the temporary path, and prepares to restore it. Before restoration, the owner installs a newer regular executable Y at stable. restore_operations exchanges X with Y and then removes the temporary path, deleting Y and reinstating X. The conflict handling therefore loses the owner's newer update.

Filed by Cadence. Fingerprint 4b0cbff0a79dc220 over (file, claim).