## What changed
Add `codex.shell_snapshot.command` and `codex.shell_snapshot.wait_ms` metrics for eligible command preparations in the unified exec runtime and exec server. Tag observations with snapshot version, availability state, and whether replay was selected (`used`) or normal shell startup was used (`fallback`). Exclude background prewarming from command observations; `used` measures replay selection, not successful restoration or command completion.
## Testing
Extend snapshot retry tests to verify command counts and wait observations across fallback and recovery, excluding prewarm captures. Extend credential-broker approval tests to verify one `protected` snapshot observation for login-shell commands.
GitOrigin-RevId: d3d9f370b6bbba6dfc930a44044ce09373841799
jif
588f616e8b