Unused package candidates from depcheck

[david-rocca]

vidence:

npm run clean reported:

• Unused dependencies: bson, express-jsonschema, jsonschema, replace-json-property, yamljs.
• Unused devDependency: standard.
• Missing dependency: mongodb.

Manual notes:

• bson is not imported directly but may be present to support the mongo-cursor-pagination override in package.json:64-67. Verify before removing the direct dependency.
• standard is not needed as a binary if ESLint plus eslint-config-standard remains the supported lint path.

Recommendation:

• Remove clearly unused packages after one PR that runs full CI.
• Keep bson only if the override requires the package to be top-level; otherwise rely on overrides.
• Add depcheck to a periodic maintenance workflow or documented release checklist.