fix: use actual daemon URL for proxy lookup in SSH connections

[vigneshakaviki]

Problem

When configuring proxies in ~/.docker/config.json, users had to use a hardcoded dummy host http://docker.example.com because SSH connections used this dummy URL instead of the actual daemon URL.

Example that used to fail:

{
  "proxies": {
    "ssh://user@host.com": {
      "httpProxy": "http://proxy.example.com:3128"
    }
  }
}

Users had to work around this by configuring proxies with the dummy host:

{
  "proxies": {
    "http://docker.example.com": {
      "httpProxy": "http://proxy.example.com:3128"
    }
  }
}

Solution

Use the actual daemon URL from the endpoint configuration instead of the hardcoded http://docker.example.com.

Now users can configure proxies with their actual SSH endpoint URLs:

{
  "proxies": {
    "ssh://user@host.com": {
      "httpProxy": "http://proxy.example.com:3128"
    }
  }
}

Changes

• Modified SSH connection helper to use the actual daemonURL for the Host field
• Added clarifying comment for command connection helper (which still uses a default since we don't have endpoint information)

The fix is minimal and only affects SSH connections, allowing proxy lookup to work with the actual configured endpoint URLs.

Fixes: #7046