Mastodon Hashtag API

Please help me write a data collection script with the EveryInfra Mastodon Hashtag endpoint (mastodon/hashtag).

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 mastodon and action to hashtag, and put the parameters inside params.
- Required parameters:
  - hashtag: Specifies the topic tag without the leading # to fetch the hashtag timeline on a target instance. Excludes boosts and replies, so it does not represent a complete sample of federated network tags.
- Optional parameters:
  - instance: Selects a Mastodon instance domain without a scheme or path. Timeline defaults to fosstodon.org and other actions default to mastodon.social.
  - limit: The most rows to return in this call, an integer from 1 to 100. The default applies when you leave it out, and a call can return fewer rows. Larger values return 422 before any charge. (default: 20)
- Returns a list of records. Main fields of each record: id, url, text, author_name, author_username, author_url, instance, like_count, reblog_count, comment_count, language, is_reblog; 15 fields in total, full list at https://api.everyinfra.com/api/v1/social/catalog?platform=mastodon.
- Example request body:
{
  "platform": "mastodon",
  "action": "hashtag",
  "params": {
    "hashtag": "art"
  }
}
- 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.