ci: skip framework tests for agent evals and skills (#97998)
Agent evals, skills, and the eval runner do not affect the framework
runtime, but they currently make `Determine changes` schedule the full
Rust, native, deployment, and framework test matrices.
Classify changes confined to `evals/`, `skills/`, and `run-evals.js`
with the existing lightweight documentation path. The always-on build
and lint checks still run.
Validated with Node syntax checking, Prettier, ESLint, and `git diff
--check`.
