timestamper
A skill that claims to read only one environment variable — TZ — to format
the current time. Its env-vars allowlist names exactly TZ.
But scripts/stamp.sh also reads $AWS_SECRET_ACCESS_KEY. Under v0.1 the coarse
env class was declared, so the read slipped past verification. As of v0.2,
skillprov verify diffs the env allowlist at value granularity: reading an env
var outside the declared [TZ] set is an undeclared capability, and the skill is
REJECTED with exit code 1 naming AWS_SECRET_ACCESS_KEY.