V3 deterministic YAML lint capability pack. By-value connector composition (service_kind=cli, no separate ingredient): the local yamllint CLI checks one trusted local YAML file or directory and returns parsable text diagnostics via the yaml.lint catalog operation. Fixed-function and reproducible: no arbitrary yamllint flags, no caller-supplied config path, no stdin stream, no strict-mode toggle, no shell wrapper, and no network egress. The built-in relaxed profile is pinned through argv so ambient .yamllint files, user config files, and YAMLLINT_CONFIG_FILE do not change pack behavior. Lint findings are represented as text output instead of failing the op; real invocation errors still fail. Requires yamllint on PATH. Local and no-egress.