Use TypeScript for all new projects

Always use TypeScript instead of plain JavaScript:
- Catch errors at compile time
- Better IDE support and refactoring
- Self-documenting code
- Safer dependency updates

Use strict mode for maximum benefit:
```json
{
"compilerOptions": {
"strict": true,
"noImplicitAny": true,
"strictNullChecks": true
}
}
```