v5.16.1 - SkillSpector follow-up

SkillSpector scan follow-up (ClawHub skill)

Security

• validate_token.py fails closed on bad expiry: grants whose expires_at is missing, non-string or unparseable are now rejected (previously treated as non-expired). Timezone-naive timestamps are read as UTC. revoke_token.py treats such grants as expired; check_permission.py --active-grants no longer crashes on naive timestamps.
• Signing key created owner-only: data/.signing_key is created with mode 0o600 via os.open instead of write-then-chmod, removing a brief readable window.

Changed

• Script header comments no longer list the modules they do not import (the list itself matched capability keywords).
• SKILL.md frontmatter declares permissions: [file_read, file_write, env].
• skill.json adds triggers, an explicit-only invocation statement, and do_not_use_for.
• check_permission.py --audit-summary --json: per-agent and per-resource counts renamed requested / granted / denied (top-level total_* unchanged).

Dependencies

Dev/CI only (Dependabot): openai 7.43.0, dotenv 18.0.9, codeql-action, ai-plugin-scanner-action.

Full suite: 3,888 tests across 42 suites; tsc --noEmit clean. See CHANGELOG.