feat: Support fetch requests

[mo2g]

Introduce FetchRequestParser to enable parsing of fetch() API calls into HTTP requests.

###
fetch("https://httpbin.org/get", {
  "headers": {
    "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7",
    "accept-language": "zh-CN,zh;q=0.9,zh-TW;q=0.8",
    "cache-control": "max-age=0",
    "priority": "u=0, i",
    "sec-ch-ua": "\"Not:A-Brand\";v=\"99\", \"Google Chrome\";v=\"145\", \"Chromium\";v=\"145\"",
    "sec-ch-ua-mobile": "?0",
    "sec-ch-ua-platform": "\"macOS\"",
    "sec-fetch-dest": "document",
    "sec-fetch-mode": "navigate",
    "sec-fetch-site": "none",
    "sec-fetch-user": "?1",
    "upgrade-insecure-requests": "1"
  },
  "body": null,
  "method": "GET",
  "mode": "cors",
  "credentials": "omit"
});