Context

This PR adds first-class support for HTTP Exchange attachments in Allure reports. Integrations can now attach one structured HTTP request/response exchange as application/vnd.allure.http+json using the .httpexchange extension. The report renders these attachments as a compact HTTP inspector with method, URL, status, duration, headers, cookies, query parameters, trailers, bodies, and errors.

The new viewer avoids unsafe HTML request/response attachments: captured content is rendered through safe text, code, table, image, and video views. HTML responses are shown as source, not executed. Redacted values stored as __ALLURE_REDACTED__ are displayed as masked placeholders, and request/response bodies can be downloaded when captured. The demo report now includes HTTP Exchange examples for JSON, form data, multipart, streaming, images, video, binary data, redirects, errors, compression, upgrades, and gRPC-style trailers.

Example attachment:

{
  "schemaVersion": 1,
  "start": 1710000186400,
  "stop": 1710000186487,
  "request": {
    "method": "POST",
    "url": "https://api.example.com/v1/orders/42?dryRun=true",
    "httpVersion": "HTTP/1.1",
    "headers": [
      { "name": "authorization", "value": "__ALLURE_REDACTED__" },
      { "name": "content-type", "value": "application/json" }
    ],
    "body": {
      "contentType": "application/json",
      "encoding": "utf8",
      "value": "{\"name\":\"demo\"}",
      "size": 15
    }
  },
  "response": {
    "status": 201,
    "statusText": "Created",
    "headers": [
      { "name": "content-type", "value": "application/json" }
    ],
    "body": {
      "contentType": "application/json",
      "encoding": "utf8",
      "value": "{\"id\":42}",
      "size": 9
    }
  }
}

Checklist

• Sign Allure CLA
• Provide unit tests