[Refactor] Use lookup map for JSON schema comparison wording

[github-actions]

WHY are these changes introduced?

The JSON schema error formatter mapped comparison operators to human-readable wording with a 14-line switch and a reassigned let. The mapping is pure data, so a lookup table states it more directly and keeps the already-long convertJsonSchemaErrors branch readable.

WHAT is this pull request doing?

Replace the switch in convertJsonSchemaErrors with a module-level comparisonDescriptions lookup map in packages/cli-kit/src/public/node/json-schema.ts. The ?? comparison fallback preserves the previous default of echoing the raw operator when it isn't one of the four known comparisons, so error messages are unchanged.

How to manually test your changes?

CI

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add