Xianyu Search API

Please help me write a data collection script with the EveryInfra Xianyu Search endpoint (xianyu/search).

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 xianyu and action to search, and put the parameters inside params.
- Required parameters:
  - keyword: The Xianyu search phrase for search, 1–100 characters. Chinese terms and model numbers match seller titles more often than English translations. It is not an item ID or a seller name.
- Optional parameters:
  - 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: 20)
- Returns a list of records. Main fields of each record: item_id (Numeric Xianyu listing ID (string)), url, title, price, original_price (Original price the seller entered, in y…), currency, city (Where the listing is, at city level as…), image_url, want_count (Number of users who tapped the want but…), tags (Every label on the listing card as writ…), category_id (Xianyu category ID (string)), free_shipping (Whether shipping is free); 19 fields in total, full list at https://api.everyinfra.com/api/v1/social/catalog?platform=xianyu.
- Example request body:
{
  "platform": "xianyu",
  "action": "search",
  "params": {
    "keyword": "iPhone 15"
  }
}
- Price: $5.56 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.