Confirms the Agent Identity fix zAI landed in 8138173: per-clone
`user.name` is sufficient for distinguishing zAI and Claude commits on
shared-Linux setups, provided each agent resets `user.name` at session
start. The one gotcha is that `.git/config` persists whichever name was
set last, so a forgotten reset silently misattributes.
Adds a dormant hooks/pre-commit guard that rejects any commit whose
`user.name` does not start with `Operator & ` (or the legacy
`Clawdie AI`). The hook only activates after `npm run install-hooks`
sets `core.hooksPath=hooks`, matching the existing opt-in pattern.
This commit itself is authored as `Operator & Claude`, proving the
mechanism end-to-end.