const employees = [
{ id: "alice", roleIds: ["server"], skillIds: ["keyholder"] },
{ id: "bob", roleIds: ["server"] },
];
const coverage = [
{ skillIds: ["keyholder"], targetCount: 1, ... }, // OK
{ skillIds: ["manager"], targetCount: 1, ... }, // Unknown skill!
];
const result = validateCoverageSkills(coverage, employees);
// result.valid = false
// result.unknownSkills = ["manager"]