Free API Documentation

Implement a typed API client for the Connectively Free API.

Base URL: https://connectively.us/api/external-users
Reference docs: https://connectively.us/api-integration/documentation/free

## Authentication
- Every endpoint except POST /login requires a JWT.
- Obtain a token via POST /login with a JSON body { "username": ..., "password": ... }. The token is returned in the `x-access-token` RESPONSE header, not the response body.
- Send that token in the `x-access-token` REQUEST header on all authenticated calls.
- Tokens expire after 24 hours — re-authenticate when a request returns 401.

## Endpoints
### Authentication
- POST /login — Authenticate free user
  Request body (application/json): { username: string (required), password: string (required, 8-30 chars) }
  Returns: JWT token in x-access-token header

### Questions
- GET /question-list — Get question list
  Query params: top_opportunities (string, optional) — If set to "true", returns top opportunities instead of regular feed questions
  Returns: array with question, source, due_date, publicLink, featuredQuestionId, sourceUrl, isHaroQuery, categories, agenticScore

## Error handling
Handle these status codes:
- 400: validation error — surface the message
- 401: token missing/expired — re-authenticate and retry once
- 403: insufficient permissions

## Requirements
- Use my project's language and HTTP conventions (default to TypeScript with fetch if unspecified).
- Expose one typed method per endpoint, with typed request and response models matching the fields above.
- Read credentials from environment variables; never hard-code them.
- Centralize auth: obtain and cache the token, attach the `x-access-token` header automatically, and transparently re-login on a 401.
- Add a small usage example showing login followed by one authenticated call.