Flickr Posts by user API

Please help me write a data collection script with the EveryInfra Flickr Posts by user endpoint (flickr/user_posts).

Endpoint contract:
- Request: POST https://api.everyinfra.com/api/v1/social with the header Authorization: Bearer <API key>. Read the key from the EVERYINFRA_API_KEY environment variable and never hard-code it.
- In the request body, set platform to flickr and action to user_posts, and put the parameters inside params.
- Required parameters:
  - user_id: Specifies the target Flickr user's NSID, such as 12345678@N04, which can be retrieved from the author_id field of search results. It does not accept display names, vanity profile aliases, or full profile URLs.
- Optional parameters:
  - author_id: Specifies the target Flickr NSID in the format 12345678@N04. This is an internal NSID—not a username—and should be extracted from the author_id field returned in search responses.
  - media_type: Filters media scope with allowed values: photos (photos only), videos (videos only), or all (all media). Defaults to photos in search and all in user_posts.
  - sort: Sorts photos and videos in search (defaults to relevance) and user_posts (defaults to date-posted-desc).
  - username: Acts as a compatibility alias for user_id in user_posts. It still requires a valid Flickr NSID rather than a human-readable display name, and public user_posts requests must still include the required user_id parameter.
  - limit: The most rows to return in this call, an integer from 1 to 50. The default applies when you leave it out, and a call can return fewer rows. Larger values return 422 before any charge. (default: 10)
- Returns a list of records. Main fields of each record: id, url, title, image_url, media_type, author_name, author_id, tags, taken_at, posted_at.
- Example request body:
{
  "platform": "flickr",
  "action": "user_posts",
  "params": {
    "user_id": "35067687@N04"
  }
}
- Price: $1.39 per 1,000 requests; failed and empty results are not charged.
- For dozens or hundreds of targets, add "mode": "async" to the body: you get a job_id at once and poll GET https://api.everyinfra.com/api/v1/jobs/{job_id} for the result.
- On 422, fix the request using the suggested parameter names and allowed values in the error; on 429 or 503, wait for Retry-After and try again.

Before writing code, ask me which targets I need, how many, which fields, and what output format I want; then confirm the plan and the rough cost with me.