[12.x] Add debug() method to HTTP client for request/response logging

[OthmanHaba]

Add debug() method to the HTTP client

I Came across a issue prevusly while debuging a thrid party integration that made me want to log my reqeuset and response for refrences i didn't find a built in method to provide me a full logging for the client

This PR adds a debug() method to PendingRequest that logs both the HTTP request and response in a human-readable format.

Usage

// Log to the default channel
Http::debug()->post('https://api.example.com/login', [
    'email' => 'user@example.com',
    'password' => 'secret',
]);

Log output

[2026-03-07 04:59:29] local.DEBUG: HTTP Request
── POST https://api.example.com/login ──
  Content-Type: application/json
  User-Agent: GuzzleHttp/7
  Host: api.example.com

  Body:
  {
    "email": "user@example.com",
    "password": "secret"
  }

[2026-03-07 04:59:29] local.DEBUG: HTTP Response
── 200 OK ──
  Content-Type: application/json
  Cache-Control: no-cache

  Body:
  {
    "token": "eyJ..."
  }

No breaking changes

This adds a new method to PendingRequest. No existing methods or signatures are modified.