ci: review driver-facing executable flags for compatibility #4643

User Story

We use OpenShell's advisory compatibility review to catch release breaks. We need it to examine executable flags used by external compute drivers so a supervisor launch change like the one in #4642 is visible before release.

Description

The compatibility review prompt names command flags, but does not explicitly tell the reviewer to inspect helper executables launched by compute drivers or to trace hidden flags, launch environment, and standard-stream contracts across revisions. Add targeted guidance for that inspection and for reporting the old and new invocation and consumer failure.

Context

Issue #4642 describes a v0.1.3 driver passing --parent-liveness-fd to a v0.1.4 openshell-supervisor, which accepts --parent-liveness-stdin instead. This task improves review coverage; it does not implement the supervisor interface or release-note changes requested in #4642.

Definition of Done

• The compatibility review prompt explicitly covers changed flags and arguments on helper executables used by external drivers.
• Reviewers trace callers and related launch environment or standard-stream changes at both revisions.
• Findings explain old and new invocations and the impact on existing external consumers.