TypeScript Discriminated Unions & Exhaustiveness Checking

Q1. Why is the 'satisfies' operator preferred over a colon type annotation (: Record<string, string | number>) in the configuration below?

const palette = {
  primary: '#0f172a',
  accent: '#38bdf8',
  spacingUnit: 8,
} satisfies Record<string, string | number>;

const upper = palette.primary.toUpperCase();

Q2. Which TypeScript type represents an unreachable code path and is idiomatically used in the default branch of a switch statement to enforce exhaustiveness?

type Status = 'draft' | 'published';

function label(status: Status): string {
  switch (status) {
    case 'draft': return 'Draft';
    case 'published': return 'Live';
    default: {
      const _exhaustive: never = status;
      return _exhaustive;
    }
  }
}

Q3. What is the effect of 'noUncheckedIndexedAccess: true' in tsconfig.json when indexing into a Record<string, Quiz>?