Setup TypeScript linting

[neno-is-ooo]

Summary

• add TypeScript-aware ESLint config
• install type packages for express, cors, figlet, jsonwebtoken, node, and supertest
• add eslint and @typescript-eslint dependencies
• convert getVersion.js to getVersion.ts

Testing

• npm test
• npx eslint 'src/**/*.ts' --fix (fails: Cannot find package '@eslint/js')