Greptile flagged that the env-access guard in
gateguard-env-documented.test.js could be bypassed via reflective reads
of process.env (Reflect.get/has/set/deleteProperty/defineProperty/
getOwnPropertyDescriptor/ownKeys), since none of the existing
UNSUPPORTED_ACCESS patterns matched that form.
Add a rule that rejects Reflect.get/has/set/deleteProperty/
defineProperty/getOwnPropertyDescriptor/ownKeys(process.env, ...) and
three self-check fixture cases (Reflect.get, Reflect.has,
Reflect.ownKeys) so the guard is pinned against silently missing them
again.
Negative control: commenting out only the new rule reproduces exactly
the reported gap (the 3 new fixture cases fail with "access guard
missed: Reflect.get, Reflect.has, Reflect.ownKeys"); restoring it goes
back to 10/10.