Contradiction: vetkd uses legacy ic-cdk caller/call API while pinning ic-cdk 0.19

[raymondk]

• skills/vetkd/SKILL.md:129 pins ic-cdk = "0.19" but the code uses the legacy API: ic_cdk::caller() (:181), ic_cdk::api::call::call(...) (:263), ic_cdk::api::call::call_with_payment128(...) (:286).
• skills/canister-security/SKILL.md (same ic-cdk = "0.19" pin, :19) uses the modern API: ic_cdk::api::msg_caller (:302), Call::bounded_wait (:346).
• skills/internet-identity/SKILL.md:43,332 and skills/multi-canister/SKILL.md:581-586 also use the modern API (msg_caller, Call::unbounded_wait).

vetkd's snippets contradict the caller-API guidance in the other skills and likely will not compile against its own declared CDK version.