Peer discovery in the four cross-model worker scripts was PATH-only, so a
Codex desktop-app install (Codex.app/Contents/Resources/codex, not linked
onto PATH) was never found and the pass silently reported "not run".
When no codex is on PATH, probe the known Codex.app bundle dirs
(CROSS_MODEL_CODEX_APP_DIRS overrides) and append the first hit, so a
PATH-installed CLI stays authoritative. Make the "no peer reachable" skip
name the peer CLIs and note that an API key alone does not enable the pass.
Document the prerequisite, bundle discovery, and Gemini's lack of a
standalone target. Add one regression test per script plus a
PATH-vs-bundle precedence case; sandboxes mask any real bundle.
Fixes#1272
Claude-Session: https://claude.ai/code/session_01SfcNrQM7jUjYiEPTc92Zw9
Trevin Chow
64785ae6f6