💡Add DEB822 installation method for the Cloudflare package repository

**Describe the feature you'd like**
A clear and concise description of the feature. What problem does it solve for you?

- Add DEB822 installation method for the Cloudflare package repository.
- I personally expect support for installing cloudflared via the DEB822 format on `Ubuntu 26.04`. Currently, the outdated `/etc/apt/sources.list.d/` is still being used for https://pkg.cloudflare.com/index.html#debian-any . See https://discourse.ubuntu.com/t/spec-apt-deb822-sources-by-default/29333 .
- A notable feature of the DEB822 format compared to `/etc/apt/sources.list.d/` is its friendliness towards `Here Documents`.

**Describe alternatives you've considered**
Are there any alternatives to solving this problem? If so, what was your experience with them?

- I don't think so.

**Additional context**
Add any other context or screenshots about the feature request here.

- See https://discourse.ubuntu.com/t/spec-apt-deb822-sources-by-default/29333 .

Start by locating the repository's Debian installation instructions and packaging entry points for cloudflared, then compare the current /etc/apt/sources.list.d/ method with the DEB822 format described in the linked Ubuntu and Cloudflare documentation. Done means Ubuntu 26.04 users have a documented DEB822 installation method for the Cloudflare package repository.

Written by the indexing model from the issue text.